Agave, agave, yucca, and agave plants all belong to the Asparagaceae family (formerly known as the Asparagaceae family). They are large plants that can grow to the height of a child or adult, and are characterized by their monocotyledonous leaves with parallel veins. Due to their impressive size and drought tolerance, they are frequently cultivated as ornamental plants in Japan. However, their many names can be confusing. Agave is a general term that includes several species such as agave and agave, while yucca is a general term that includes several species such as yucca. Agave and yucca are distinguished by the shape of their flowers. The only difference between agave and agave is the color. Agave is sometimes called the "plant of the century" and is said to be the raw material for tequila, but these are not entirely factual. This article will explain the classification, ecology, and culture of agave.

What are Agave, Agave serrata, Yucca, and Yucca?

Agave americana subsp. americana, also known as the blue agave, is native to Mexico and Texas in the United States. It is cultivated as an ornamental plant worldwide, including in Japan, and has naturalized in some countries. This evergreen perennial thrives in hot climates and drought-prone areas. It is also used for fiber and as a raw material for fermented alcoholic beverages (pulque octori) and distilled spirits (mezcal).

Agave americana 'Marginata' is a cultivated variety of Agave americana. It is grown for ornamental purposes all over the world, including Japan.

Agave is a general term for plants belonging to the genus Agave (Agave genus), and in addition to the two species mentioned above, it also includes Agave stricta and Agave victorae-reginae.

Yucca gloriosa var. recurvifolia, also known as Kimigayo Orchid, is a variety of Yucca gloriosa var. gloriosa and is an evergreen shrub native to the southeastern United States. It is cultivated as an ornamental plant worldwide, including in Japan.

Yucca is a general term for plants belonging to the genus Yucca (also known as the genus Yucca), and includes the two species mentioned above, as well as Yucca flaccida and Yucca aloifolia. Another name for it is "Youth Tree."

All of these plants belong to the Asparagaceae family (formerly known as the Asparagaceae family), and are characterized by their large size, sometimes reaching the height of a child or adult, and their monocotyledonous leaves with parallel veins. Due to their impressive appearance and drought tolerance, they are frequently cultivated as ornamental plants in Japan.

[Seed Plant Encyclopedia #087] What are the species of the Asparagaceae family? Photo list

The Asparagaceae family, also known as the Asparagaceae family, consists of perennial herbs, woody plants, or vines. They have rhizomes or bulbs. Leaves are alternate, opposite, or whorled, and may be clustered at the base of the stem. The terminal branches may also be leaf-like (Asparagus genus, Ruscus aculeatus...).

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However, these terms seem to be sometimes confused on the internet. Some websites mistakenly refer to Yucca glauca as Agave.

Although both agave and Yucca have "ran" in their names, they do not belong to the orchid family. Orchids have showy "orchid-shaped corollas" in which petals and sepals are cleverly combined, but these flowers do not have that shape.

What is the difference between agave and yucca?

As mentioned above, "agave" refers to several types of plants, including the Japanese agave (agave americana), while "yucca" refers to several types of plants, including the Japanese yucca (Yucca glauca).

So, what are the differences between agave and yucca?

The difference between the species listed here is between Agave americana, Agave serrata, and Yucca glauca.

A key difference in classification is that agaves produce upward-facing flowers only once every few decades per plant, and these flowers consist only of short, green perianth segments (where the distinction between petals and sepals is unclear), whereas yucca plants produce downward-facing flowers irregularly every year from May to October, and these flowers have large, white perianth segments (Flora of North America Editorial Committee, 2002).

This difference is largely due to the pollination ecology in their original habitats, specifically the types of animals that carry pollen for pollination.

Agave plants are generally pollinated by nocturnal bats, which provide nectar and pollen to bats at night, allowing the bats to carry the pollen to other plants (Trejo-Salazar et al., 2016; Eguiarte et al., 2021). Therefore, they lack prominent perianth segments, an adaptation for bats which do not rely on their vision at night. However, there are rare species, such as Agave americana, that are also visited by diurnal hummingbirds (Knudsen & Tollsten, 1995).

On the other hand, yucca is pollinated by insects, and only specific moths called yucca moths visit each species (Kawakita, 2012; Ishii, 2020). The female moth lays her eggs on the pistil of the yucca, which serve as food for her larvae, and in return, she uses her antennae to scrape pollen out of the yucca and carry it away. For this reason, the perianth segments of the yucca are white and downward-facing to make them conspicuous to the moths and allow them to burrow in. This relationship is known to have an almost one-to-one correspondence between each yucca species and the moths that visit, and is called "obligate pollination symbiosis."

Considering these significant ecological differences, it becomes clear that although they may seem similar, they are entirely different species.

Furthermore, while agave stems are very short or indistinct and give the impression of being almost entirely made up of leaves, yucca forms a trunk covered in leaves.

In the case of Agave, Agave americana, and Yucca glauca, the leaves are completely different. Agave leaves are wide, fleshy, and spiny, while Yucca leaves are narrow, thin, and spineless.

What is the difference between Agave and Agave americana?

What are the differences between Agave and Agave americana?

Actually, as you can see from the scientific name, "agave" is a cultivated variety of "Agave americana." Therefore, you can assume that their basic form and ecology are exactly the same.

While the scientific name is derived from "Ao-no-ryūzetsuran" (blue ryūze), the Japanese name is derived from "ryūzetsuran" (blue ryūzetsuran), so note that the order of naming is reversed. This means that Ao-no-ryūzetsuran is actually the original, wild type. A misunderstanding likely arose during the process of its introduction to Japan.

The main difference is that the leaves of Agave japonica have white variegation along the edges, while those of Agave americana are uniformly bluish-green without this characteristic.

Everything else is exactly the same.

Is it a myth that agave plants live for 100 years? Why don't they flower for such a long time?

Agave is sometimes called the "plant of the century" due to its long lifespan, and in Japan, it is sometimes said to live for 50 to 100 years or more. Is this really true?

Although I couldn't find any actual scientific papers, this is probably an exaggeration, and according to English-language sources such as the English Wikipedia, they typically live for 10 to 30 years.

It's possible that the environment in Japan differs from that of its country of origin, slowing down its growth and potentially allowing it to live for 50 to 100 years, but this has likely not been scientifically verified.

Also, if "ryūzetsuran" means "agave (genus Agave)" and includes other types of agave, then this rule might not apply.

However, it is true that they live for a very long time. Moreover, at the very end of their life, they bloom profusely just once, secreting pollen and nectar. Once flowering is over, they die and wither away. This is a characteristic of plants called "monovolent plants." Why do they do this? It seems that this would reduce the opportunities for pollination and make it difficult to leave offspring.

This is thought to be related to adaptation to bat pollination, as mentioned above (Eguiarte et al., 2021).

Agave plants are known to store agua miel (agave syrup) in their stems to provide bats with an abundance of pollen and nectar as food. This syrup is very sweet and can be consumed by humans as is, or used to make alcoholic beverages such as pulque and mezcal (tequila is one type), as described later.

The reason they have a long lifespan and rarely bloom is because their production takes a very long time.

But if that's the case, why did bat pollination evolve in the first place?

One major reason for this is likely the scarcity of pollinating insects and birds in the hot, drought-prone regions where agave originates. In the case of Agave americana, diurnal hummingbirds also contribute to pollination (Knudsen & Tollsten, 1995).

Although I said that they wither and reach the end of their lifespan, they do produce fruit and continue to grow as the next generation by sending out adventitious buds from the base. Therefore, they will never become extinct.

Is it a myth that agave is used to make tequila?

A common misconception is that agave is used to make tequila.

In volume 5 of the manga "Moyashimon," which I loved reading when I was a student, there is a scene where Takuma Kawashima, a student who has returned from Mexico, cuts down an agave plant on campus (!) and uses the agua miel (agave syrup) as an ingredient for pulque (fermented agave liquor). In that scene, he says something to the effect that "agave is used as an ingredient for tequila."

However, this statement is somewhat misleading. If "ryūzetsuran" means "agave (genus Agave)," then there is no problem, but if it means " Agave americana," then it is incorrect.

This is because the Tequila Regulatory Board has clearly defined, for brand protection purposes, that "tequila refers to a beverage produced in the town of Tequila and using tequila agave (Agave tequilana) as its main ingredient" (Kuramitsu, 2021). This is the same as with wine.

Tequila agave looks quite similar to agave green (and agave), but it is a completely different species with red spines on its leaves. It is also distributed only in Mexico and does not grow in the United States like agave green, and it is probably difficult and rare to cultivate it in the wild in Japan.

However, tequila is a type of Mexican distilled spirit made primarily from mezcal, which is made from agave, and mezcal itself can sometimes be made from the blue agave plant. I'd like to ask someone who has actually tasted it how it differs from tequila.

References

Eguiarte, LE, Jiménez Barrón, OA, Aguirre-Planter, E., Scheinvar, E., Gamez, N., Gasca-Pineda, J., … & Souza, V. 2021. Evolutionary ecology of Agave: distribution patterns, phylogeny, and coevolution (an homage to Howard S. Gentry). American Journal of Botany 108(2): 216-235. https://doi.org/10.1002/ajb2.1609

Flora of North America Editorial Committee. 2002. Flora of North America (Vol. 26 Liliidae). Oxford University Press, ‎Oxford. 752pp. ISBN: 9780195152081

Ishii, Hiroshi. 2020. The Resilient and Wonderful Relationship Between Flowers and Insects: Ecology Related to Pollination. Bere Publishing, Tokyo. 290pp. ISBN: 9784860646103

Knudsen, JT, & Tollsten, L. 1995. Floral scent in bat-pollinated plants: a case of convergent evolution. Botanical Journal of the Linnean Society 119(1): 45-57. https://doi.org/10.1111/j.1095-8339.1995.tb00728.x

Kawakita, Atsushi. 2012. How did obligate pollination symbiosis cross the ocean? – Island biogeography of symbiotic systems of the Phyllanthaceae family and the genus Phyllanthus. Journal of the Ecological Society of Japan 62(3): 321-327. https://doi.org/10.18960/seitai.62.3_321

Kuramitsu, Jun. 2021. Authentic Shochu as seen from the export strategies of tequila and mezcal. Journal of the Brewing Society of Japan 116(2): 77-88. ISSN: 0914-7314, https://agriknowledge.affrc.go.jp/RN/2030937155

Trejo-Salazar, RE, Eguiarte, LE, Suro-Piñera, D., & Medellin, RA 2016. Save our bats, save our tequila: industry and science forces join to help bats and agaves. Natural Areas Journal 36(4): 523-530. https://doi.org/10.3375/043.036.0417

The family Asphodelaceae, also known as the Asphodelaceae, is characterized by its linear leaves and flower stalks that rise from between the leaf clusters. It consists of three subfamilies and approximately 35 genera: Asphodeloideae (about 15 genera including Asphodelus, Kniphofia, and Aloe), Xanthorrhoeoideae (only Xanthorrhoea in Australia), and Hemerocallidoideae (about 20 genera mainly in the Southern Hemisphere, East Asia, and Europe, including Dianella, Phormium, and Hemerocallis). In Japan, Dianella ensifolia (found in the Kii Peninsula of Honshu, Shikoku, Kyushu, the Ryukyu Islands, and the Ogasawara Islands) and Hemerocallis are native. In the APG III system, the family name Xanthorrhoeaceae was used, but in the APG IV system, Asphodelaceae is used. Regarding the Japanese names of the families, the former Xanthorrhoeaceae was called Susunoki-kae and the former Asphodelaceae was called Tsuruboran-kae, but since the genera Susunoki and Tsuruboran are not native to Japan and are unfamiliar taxonomic groups, the Japanese name "Wasuregusa-kae" has been proposed since the APG III system.

This article provides a comprehensive, illustrated guide to plants belonging to the Hemerocallis family.

The basic information is based on Tsukamoto (1994) and the Kanagawa Prefectural Flora Survey Association (2018). Photographs are replaced as better ones become available. While the identifications are made by the author, please note that they may be changed without notice if misidentifications are found.

No.0519 Maoran Phormium tenax

This evergreen perennial plant is also known as New Zealand flax or New Zealand hemp. Its leaves, which have yellow vertical stripes, are long, narrow, pointed at the tip, and glossy, reaching up to 2 meters in length. The leaves grow in clumps, from which flower stalks emerge, bearing bright red or yellow flowers. It is endemic to New Zealand and Norfolk Island in Australia. It is an introduced species on several Pacific islands and in Australia. It can be found in lowlands, riverbanks, and wetlands in low mountainous areas. After the arrival of the Maori people in New Zealand, its fibers were widely used in traditional Maori textiles. After the arrival of Europeans, it was also used as a material for ropes and sails, at least until before World War II.

No.0520 Daylily Hemerocallis fulva var. longituba

This is a perennial herb. The leaves are narrow and green. It flowers in July and August. The flower stalks are 50-70 cm tall. The flowers have six petals. They are usually orange-red, but occasionally some lack the red markings. The leaves wither in winter. Typical characteristics include narrow leaves, a bifurcated inflorescence with a narrow flower stalk, and a long flower tube, but some individuals are difficult to distinguish from Hemerocallis fulva. After flowering, the flowers fall off along with the ovary, and fruiting is rare. It is distributed in Honshu, Shikoku, and Kyushu, and grows on riverbanks, rice paddy ridges, and grasslands at the edges of forests.

No.0521 Hemerocallis fulva var. kwanso

This is a perennial herb. Its leaves are broad, yellowish-green, and grow densely. It flowers from July to August, and in this prefecture, the flowering period is from the end of June to July. The flower stalks are 50 to 100 cm tall. The flowers are orange-red, double-petaled, and the stamens have transformed into petals. It is triploid and therefore does not produce fruit. It is distributed in Hokkaido, Honshu, Shikoku, Kyushu, and China. It grows on riverbanks, rice paddy ridges, and in gardens. Like the red spider lily, it is said to be a prehistoric naturalized plant that was introduced to Japan from China in ancient times, but it does not grow wild in China (although it is cultivated there), and the origin of its place of origin is unclear.

No.0524 Hemerocallis citrina var. vespertina

This is a perennial herb. Its Japanese name comes from the fact that its flowers open in the evening and wilt by the morning of the next day, and its leaves resemble those of a sedge. The stems reach a height of 100-150 cm. The roots are yellow and stringy and do not form clumps. The basal leaves are linear, 40-50 cm long and 5-15 cm wide, growing in two rows and fanning out, with only the upper part slightly drooping. At the tip of a single stem, the inflorescence branches out, bearing successive upward-facing, trumpet-shaped, lemon-yellow flowers. Unlike Hemerocallis fulva, anthocyanins are not synthesized in the flowers, and the petals are not reddish. The petals are deeply divided into six lobes and have a slight fragrance. The length and width of the perianth segments vary from individual to individual, with the perianth segments being 6.5-7.5 cm long and the corolla tube being 2.5-3 cm long. The stamens are shorter than the perianth segments, the anthers are blackish-purple, and the style is slightly longer than the stamens. The flowering period is from July to September. The flowers open in the evening and wilt by the following morning. The capsule is broadly oval, about 20 mm long, with a notched tip. The seeds are about 5 mm long, black, oval-shaped, and glossy. It is distributed in Siberia, northeastern China, the Korean Peninsula, and Honshu, Shikoku, and Kyushu in Japan. It grows in somewhat dry places such as mountain grasslands and forest edges. It is pollinated by hawk moths, and it is known that the yellow corolla, fragrant flowers, short pistil, and long corolla tube evolved from flowers pollinated by butterflies and bees (Nitta et al., 2007).

No.0524.a *Xanthorrhoea preissii*

An evergreen shrub, also known as grass tree. It grows to a height of 1-2 meters. The leaves are silvery-white, long, narrow, and very stiff. They are about 4 mm wide and 60-100 cm long. The flower stalks are very long, about 1 meter. The flowers are whitish-green and densely packed in spike-like inflorescences. The spike-like inflorescence itself is also about 1 meter long. It is a very slow-growing plant. Although bushfires are common in Australia's native forests, the grass tree can withstand them and survive, with only its surface being charred. It is found in the dry native forests of southwestern Australia. When the stem of the grass tree is wounded, a yellow resin is released, which becomes rubbery and is called grass tree gum locally.

No.0525.a Hana Aloe Bulbine frutescens

An evergreen perennial herb, also known as Bulbine frutescens. It grows in clumps, reaching a height of 25-60 cm. The leaves are fleshy, narrow, lanceolate, and about 15 cm long. It flowers from April to November. Long flower stalks bear small, star-shaped flowers with six petals in a raceme. The petals are orange, yellow, and white. The stamens are densely covered with fine hairs. Each flower lasts only one day, but it blooms continuously. It is heat tolerant. Native to South Africa, it is cultivated in Japan.

No.0526 Aloe arborescens

This evergreen perennial herb is also known as Aloe arborescens. The name "Rokai" is a phonetic pronunciation of its Chinese name, 蘆薈 (Luhui). Native to South Africa, it grows to a height of 1-2m, branching profusely and forming clumps. The leaves are densely covered with horny, triangular spines along the margins. The leaves are 45-60cm long and 5cm wide, grayish-green to green, sword-shaped, and densely arranged. The flowers are cylindrical, 4cm long, bright red, and form racemes. Native to southern Africa, it is used as a folk remedy for stomach ailments and constipation, with the transparent, fleshy part of the fresh leaves being eaten, the dried leaves being brewed as aloe tea, and the juice of the fresh leaves being applied externally to treat athlete's foot and burns. Because it is a medicinal herb that cools the heat in the stomach and intestines and treats inflammation, it is contraindicated for people with sensitive stomachs and pregnant women. In Japan, Aloe vera is more commonly consumed as food. A bird called the sunbird, which has a long beak, comes in search of nectar and pollinates the flowers (Hargreaves et al., 2012).

No.0526.a Aloe x nobilis

An evergreen perennial herb. Its name in Japanese is Fuyajo (不夜城), meaning "nightless castle." There are various theories, but it is generally considered to be an artificial hybrid of Aloe mitriformis (broad-leaved nightless castle), native to South Africa, and Aloe arborescens, or Aloe mitriformis and Aloe brevifolia (dragon mountain) (Smith & Figueiredo, 2015). It is succulent. The stems are erect, succulent, thick, and soft. The leaves are succulent, green, and triangular, with spiny serrations along the edges, and sparsely covered with short, yellowish-white spines on the outside of the leaves. They are densely arranged alternately in a spiral pattern. In winter, the leaves take on a slightly reddish tint. In plants several years old, around June, flower stalks emerge from the leaf axils, forming spindle-shaped inflorescences and bearing orange, tubular flowers. It is distinguished from *Hypochaeris erythrosora* by the size of its leaves, the shortness of its flowers, and the longness of its bracts. Since no wild individuals have been found in South Africa, it is thought to have originated from hybridization between cultivated plants in Europe. It has naturalized in parts of Portugal and is also cultivated in Japan.

References

Hargreaves, AL, Harder, LD, & Johnson, SD 2012. Floral traits mediate the vulnerability of aloes to pollen theft and inefficient pollination by bees. Annals of Botany 109(4): 761-772. https://doi.org/10.1093/aob/mcr324

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Nitta, Kozue; Hasegawa, Masahiro; Miyake, Takashi; Yasumoto, Akiko; and Yahara, Tetsuichi. 2007. Investigating the genetic basis of floral traits related to pollination syndromes in Hemerocallis fulva and Hemerocallis fulva. Journal of the Ecological Society of Japan 57(1): 100-106. https://doi.org/10.18960/seitai.57.1_100

Smith, GF, & Figueiredo, E. 2015. Notes on Aloe × nobilis Haw. (Asphodelaceae: Alooideae). Haseltonia 21: 72-76. https://doi.org/10.2985/026.021.0110

Tsukamoto, Yotaro. 1994. Encyclopedia of Horticultural Plants, Compact Edition. Shogakukan, Tokyo. 3710pp. ISBN: 9784093051118

Orchids (Orchidaceae) are terrestrial, epiphytic, lithophytic, and mycoheterotrophic perennial herbs. Stems are monoaxial (monostalked) or sympodial (compound), with long stems, rhizomes, or enlarged pseudobulbs. Leaves are mostly flattened, with a tubular sheath at the base, sometimes reduced to scales. Flowers are bilaterally symmetrical, bract-bearing, and arranged in spikes or racemes, rarely solitary. There are typically three sepals and three petals, although some species have fused lateral sepals. The three sepals are almost identical. The two lateral petals are similar, but the central one, called the labellum, is distinctive in shape, size, and color, and sometimes has a spur at its base. In most cases, the stamens and pistil are fused to form a column, with the anthers on the upper surface and the stigma on the lower surface. Generally, part of the stigma is modified to form a beak. The anthers are usually two-chambered, containing 2 to 8 pollinia, which are aggregates of waxy or powdery pollen, with the base typically attached to a sticky substance. The fruit is mostly a capsule that splits into three sections, and the seeds are extremely small. They are widely distributed throughout the world, with approximately 860 genera and 26,000 species known globally, and approximately 86 genera and 320 species known in Japan.

This article provides a comprehensive, field guide-style introduction to orchid species.

The basic information is based on Tsukamoto (1994) and the Kanagawa Prefectural Flora Survey Association (2018). Photographs are replaced as better ones become available. While the identifications are made by the author, please note that they may be changed without notice if misidentifications are found.

No. 0373 Hemipilia graminifolia var. graminifolia

This is a deciduous perennial herb. The rhizome is oval-spherical with a few fibrous roots. The stem is erect or ascending depending on the growing environment, reaching a height of 5-20 cm, with 2-4 leaves clasping the stem. It flowers from July to August. 3-12 flowers bloom at the top of the stem, usually facing in one direction, and are typically reddish-purple, although there is considerable individual variation in flower color. The bracts are narrowly lanceolate. The dorsal sepal is ovate, and the lateral sepals and petals are obliquely ovate. The dorsal sepal and lateral petals meet at the tip, forming a helmet-like shape. The labellum is longer than the sepals and deeply 3-lobed, with a thick spur that does not taper at the tip and is slightly curved. The capsule is cylindrical. It is distributed in Honshu, Shikoku, Kyushu, and Korea. It grows in slightly damp, rocky areas in mountainous regions.

No.0374.a Okinawa Plover (Hemipilia lepida)

This is a perennial herb, growing to a height of 10-15 cm. The stem emerges from an oval-shaped tuber at the tip of a slender stolon. There are 2-4 leaves at the base, which are oblong and somewhat broad, 4-8 cm long and 1.5-2.5 cm wide. It flowers from February to April. The flowers are pale pink, with several flowers growing at the end of the stem. They are pale reddish-purple, and the labellum is 8-10 mm long, deeply 3-lobed, with the central lobe further divided into two. The calyx is oblong, 4-6 mm long, and the lateral petals are slightly shorter than the sepals. The spur is 4-5 mm long and slightly shorter than the ovary. It is endemic to Japan, distributed from Kyushu (southern part) to Okinawa, and inhabits crevices on damp rocks and grasslands along the coast.

No.0386 Habenaria radiata (Egret Flower)

This is a perennial herb. The stem grows tall and solitary, reaching 15-50 cm, and bears 1-3 white flowers near the tip. It flowers from July to August. The flower is about 3 cm in diameter, with a large, deeply arranged labellum. The central lobe is lanceolate, while the lateral lobes are obliquely fan-shaped, spreading laterally with finely divided edges. The Japanese name comes from the fact that the open labellum resembles a white heron spreading its wings. The lateral petals are white and distorted ovate. The spur hangs down to a length of 3-4 cm, gradually thickening at the tip, where nectar accumulates. The flower has almost no fragrance, but occasionally some individuals exhibit a noticeable scent. The two anther locules are parallel, and each contains a yellow, ovate pollinia. The bracts are about 5 mm long and ovate-lanceolate. The three sepals are green, with the dorsal sepal being broadly ovate and the lateral sepals on either side being distorted ovate, about 8 mm long. There are a few thick roots underground. Several thick rhizomes, which closely resemble roots, also grow, and the tips of these rhizomes swell into tuberous structures, with only these parts surviving the winter. The following year, rhizomes emerge from these bulbs. There are 3-4 basal leaves at the base of the stem, and a few scale leaves above them. The leaves are alternate, with the lower leaves being larger, and are elongated linear, 5-10 cm long and 3-6 mm wide. It is distributed in the Korean Peninsula, the Russian Far East, eastern China, and Japan (Hokkaido, Honshu, Shikoku, and Kyushu), and inhabits slightly damp places.

What species resembles the egret orchid? The flowers are visited by hawk moths! And not only that, tiny insects called thrips also play an important role in pollination! What is the "Egret Orchid Legend"?

The egret orchid (Habenaria radiata) is a perennial plant that inhabits slightly damp areas and is a popular choice for gardening. Unfortunately, due to the decline of its wetland habitat and illegal harvesting, it is listed as near-threatened on the Ministry of the Environment's Red List. There are many closely related species, and many that share the name "egret orchid," but this particular species has a flattened stem resembling a heron…

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No. 0422 Vanilla planifolia

Commonly known as vanilla, it is a climbing perennial evergreen epiphytic orchid. It has adhesive roots. Its vines (stem) grow by twining around trees and other objects. They can grow to over 60m in length. Racemes of several fleshy, yellowish-green flowers, about 6cm in diameter, bloom from the leaf axils from spring to early summer. The flowers are not fragrant. The fruit that develops after flowering is a slender, cylindrical capsule. The fruit is initially green, but turns glossy purplish-brown when ripe. The pod contains countless tiny black seeds. The seeds are used as a raw material for fragrances, but the harvested seed pods have no scent. Only through repeated curing, fermentation, and drying does the pod develop its unique sweet aroma, gradually producing the sweet-smelling vanilla beans. This scent is mainly due to vanillin. By extracting the components of vanilla beans and dissolving them in a solvent, vanilla essence or vanilla oil can be produced. These are used medicinally for treating hysteria and as sedatives, and to flavor chocolate, ice cream, and confectionery. Native to Mexico and Central America, it is cultivated in hot and humid tropical climates. It is believed that cultivation began with the Totonaco people living on the eastern coast of Mexico to add it to a drink called xocolatl, which is made from cacao. In the 15th century, the Aztecs, who conquered the Totonaco, acquired vanilla, and it eventually fell into the hands of the Spanish, who conquered the Aztecs. There is also a theory that the conqueror Hernán Cortés brought it back to Europe. Originally used as a flavoring for chocolate, in the early 17th century, Hugh Morgan, the pharmacist to Queen Elizabeth I of England, used it in confectionery, and the Queen highly valued it. Even today, production takes a long time, so supply cannot keep up with demand, making it the second most expensive spice in the world, with 99% of the market being synthetic vanilla. Because stingless bees, a species endemic to Central America, visit the flowers, pollination was not possible outside of this region. However, in 1841, on the French colony island of Réunion in the Indian Ocean, a 12-year-old slave boy named Edmond Albius devised a method for artificially pollinating vanilla (Odoux & Grisoni, 2010).

No.0433 Spiranthes sinensis subsp. australis

Also known as Mojizuri. The stems are 10-40 cm tall. The leaves are broadly linear, with 2-3 leaves arranged alternately at the base. The flowering period is from May to August. The flowers are pale pink and usually grow in many spirals at the top of the stem. The sepals and lateral petals are lanceolate. The labellum is white, obovate, with a downward-curving tip and serrated edges. The capsule is elliptical. It is distributed in Hokkaido, Honshu, Shikoku, Kyushu, the Ryukyu Islands, the Ogasawara Islands; Asia south of Sakhalin, Australia, Tasmania, and New Zealand. It prefers sunny grasslands and lawns. It grows in grasslands, lawns, and roadsides throughout the region and is the most common of the wild orchids. Known varieties include autumn-blooming f. autumnus and white-flowered f. albescens. The scientific name 'Ylist' is used. It has been found that twisting the inflorescence prevents pollination of neighboring flowers by leafcutter bees, which are pollinating insects, but at the same time reduces its appeal to bees. For this reason, the degree of twisting varies depending on the number of leafcutter bee populations present (Hayakawa and Sueji, 2017).

No.0433.a Spiranthes sinensis subsp. sinensis

This is a perennial herb, growing to a height of 20-50 cm. It has 2-3 leaves, broadly linear, 5-20 cm long and 0.3-1 cm wide. The tips are acute, and the base forms a sheath. It flowers from March to May. The flowers are pale pink and resemble those of Spiranthes sinensis, but the inflorescence is hairless. It is distributed from Hachijojima, Aogashima, the Nansei Islands (south of the Amami Islands) to tropical Asia and Australia. It grows in grasslands and lawns. The scientific name 'Ylist' is used.

No.0439.a Goodyera hachijoensis var. yakushimensis

This is a perennial herb, growing to a height of 10-25 cm. The stem has a long, creeping base and an upright upper section. It has 3-4 leaves, with oblique-ovate-elliptic to narrowly ovate blades, 4-8 cm long. White spots run in a band along the midrib. It flowers in October. The flowers are densely packed in racemes at the top of the stem and are pale pink. The bracts are linear-lanceolate with an acute apex. The dorsal sepal is ovate, and the lateral sepals are oblong-ovate-ovate, about 4 mm long. The lateral petals are oblanceolate, almost the same length as the sepals. The labellum is broadly ovate, with a white, vesicular swollen portion at the base. It resembles *Aster tataricus*, with white spots along the midrib of the leaves, but differs in that its leaves are slightly longer (about 4-8 cm) and the swollen portion at the base of the labellum is white instead of yellow. It is distributed in Kyushu (southern Kyushu and Yakushima). It inhabits evergreen broadleaf forests.

No.0442 Bletilla striata

This is a deciduous perennial herb. The pseudobulbs are somewhat flattened and grow in clusters along the ground surface. The leaves are lanceolate-oblong, 20-30 cm long and 2-5 cm wide. The flower stalk emerges from a sheath-like center as the leaves unfold, reaching a length of 30-70 cm. It flowers from April to May. The flowers are reddish-purple and borne in groups of 3-7. The bracts are lanceolate-elliptic and deciduous. The labellum is wedge-shaped and obovate, with three lobes at the tip. The lateral lobes are inwardly curved, surrounding the column, while the central lobe is rounded with a curled edge and has five irregular ridges on its inner surface. The capsule is spindle-shaped. It is distributed in Honshu (west of Fukushima Prefecture), Shikoku, Kyushu, the Ryukyu Islands, southern Korea, China, and Taiwan. It grows in sunny, slightly damp grasslands and slopes. It rarely grows wild in damp sloping forests and cliffs, but it is commonly cultivated in gardens and other places, so there are many lost specimens.

What species resembles the Bletilla striata (purple orchid)? Recent research has revealed that the flowers not only deceive bees, but also utilize male bees for courtship!

Bletilla striata is a perennial herb that is naturally distributed from Honshu to Okinawa in Japan, but wild specimens are classified as near-threatened. On the other hand, it is also a popular ornamental plant and can be seen in almost every town. While it was once thought that the wild population in Japan consisted of escaped cultivated plants, it is now believed that the wild population is...

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No.0442.1 White-flowered Bletilla striata f. gebina

A variety of Bletilla striata with white flowers. It can be found both in the wild and in gardens.

No.0445 Cochran (Liparis nervosa)

This is a terrestrial perennial herb. The pseudobulb is cylindrical with 2-3 nodes and is about 6 cm tall. The leaves are broadly oval, with 2-3 leaves growing close together at the top. The flower stalk is 15-30 cm tall. It flowers from June to July. 5-10 flowers are borne on the flower stalk and are dark reddish-purple. The bracts are membranous and triangular. The sepals are narrowly oblong. The lateral petals are oblanceolate-linear. The labellum is wedge-shaped-obovate with minute serrations on the margin and a shallow groove in the center. The upper half is recurved, and there are pointed projections on both sides of the inner surface of the base. The column is slightly curved forward and 3 mm long. The capsule is club-shaped-fusiform. It is distributed in Honshu (south of Fukushima Prefecture), Shikoku, Kyushu, the Ryukyu Islands, Korea (Jeju Island), China, Taiwan, and Southeast Asia. It grows on the forest floor of evergreen broad-leaved forests.

No.0456 Ebine Calanthe discolor

This is an evergreen perennial herb. The pseudobulbs are ovate and grow in a rosary-like pattern near the ground. The leaves are 2-3 in number, elliptical, basal, and hairless. The flower stalk is 20-40 cm tall, with 1-2 lanceolate scale leaves and short hairs. It flowers from April to May. 5-20 flowers bloom on the upper half of the flower stalk, usually dark brown to pale purplish-brown (flower shape and color vary considerably depending on the distribution area). The bracts are lanceolate. The sepals are narrowly ovate and spread flat, and the lateral petals are narrower than the sepals. The labellum is fan-shaped and 3-lobed, with the central lobe shallowly 2-lobed at the tip. It also has 3 raised lines in the center. The spur is 5-10 mm long. The capsule is obovate. It is distributed in Hokkaido (southwestern part), Honshu, Shikoku, Kyushu, Ryukyu Islands; Korea (southern part); and China. It grows in woodlands in mountainous areas and often forms colonies in suitable habitats. However, its population has drastically decreased due to land development and overharvesting.

No.0461.a Phaius tankervilleae

This is a perennial herb, growing to a height of 60-120 cm. It has an ovate-conical pseudobulb at its base. Four to six leaves grow on the pseudobulb; the leaf blades are oblong-lanceolate to oblong, 40-80 cm long and 6-15 cm wide. The tips are acute, the leaves are thick and herbaceous, slightly glossy, and have many longitudinal wrinkles. It flowers from April to June. Four to ten flowers are borne in a raceme at the top of the stem. The bracts are oblanceolate and fall off after flowering. The sepals and lateral petals spread flat, 5 cm long and 1-1.5 cm wide, white on the outside and reddish-brown on the inside. The labellum is rectangular-elliptic and rolled into a tube, 4-5 cm long, white at the base and dark reddish-purple in the upper half, shallowly 3-lobed at the tip, with rounded lobes and wavy margins. The spur is cylindrical, about 1 cm long, and the column is about 2 cm long. It is distributed in Japan from Kyushu (south of Tanegashima) to Okinawa, southern China, Taiwan, tropical Asia, and Oceania. It inhabits the forest edges under evergreen trees.

No. 0462 Cremastra variabilis

This is a perennial herb. The pseudobulbs grow shallowly underground, somewhat spaced apart and arranged horizontally. The leaves are leathery, oblong, with a narrowed petiole at the base and three prominent main veins. After flowering, the leaves temporarily wither, and new leaves emerge in autumn to overwinter. The flower stalks arise from the sides of the pseudobulb apex and reach a height of 30-50 cm. The flowering period is from May to June. The flowers number 8-20 and are borne laterally, with much variation in color from pale green to reddish-purple. The sepals and lateral petals are linear-lanceolate. The labellum is 3 cm long and has vivid reddish-purple markings. The base is swollen and surrounds the column. The lateral lobes are small and lanceolate, while the central lobe is oblong and greatly recurved. The column is 2.5 cm long and slightly thickened at the tip. The capsule is oblong. It is distributed in Hokkaido, Honshu, Shikoku, Kyushu, Ryukyu Islands, southern Sakhalin, Korea, China, Taiwan, Indochina, Thailand, and the Himalayas. It grows in forests in mountainous and hilly areas. The species previously identified as C. appendiculata is now considered a separate species. In 'Ylist', it is listed as C. appendiculata var. variabilis.

No.0465 Dendrobium moniliforme

This is an evergreen perennial herb. The stems grow in clumps, are slender and cylindrical, and reach a height of 5-30 cm. The leaves are lanceolate, with the base forming a leaf sheath that encloses the internodes. It flowers from May to June. The flowers grow in inflorescences from the nodes of the stems that have shed their leaves the previous year, bearing 1-2 flowers, and vary greatly in color from white to pale pink. The sepals are lanceolate. The lateral petals are the same shape as the sepals but slightly shorter. The labellum is ovate-triangular, with the base edge curving outward upwards and surrounding the column. It also has pale purple spots and glandular hairs from the center to the base. The glandular hairs become longer towards the base. The column is very short. The capsule is obovate-lanceolate. It is distributed in Honshu (south of Iwate Prefecture), Shikoku, Kyushu, the Ryukyu Islands, southern Korea, China, and Taiwan. It grows in clusters on tree trunks and rocks in sunny locations. Those growing in particularly conspicuous locations are often lost due to horticultural collection, and only a few remain in high places along steep stream beds.

No. 0468 Hinoderan Cattleya labiata

Also known as Cattleya, this epiphytic plant has a flower stalk that grows upright from the top and bears 1 to 30 flowers. The flowers are large and beautiful. The sepals and lateral petals are separate, with the lateral petals being wider than the sepals. The labellum is separate and usually three-lobed, with the base rolled into a tube to enclose the column, and the central lobe spreading widely. The column is almost rod-shaped. There are four pollinia. It is distributed in the mountain ranges of the Atlantic coast at the mouth of the Amazon River in northwestern Brazil, at altitudes of 500 to 1000m. It inhabits hard granite rocky areas with a few shrubs and grasses. It was once discovered by William Swainson and presented to a botanical garden, becoming an indispensable part of horticulture, but the exact collection location was lost, leading to its rediscovery. The horticultural population commonly called "Cattleya" includes intergeneric hybrids. The following specimen appears to be a variety called Irene Finney 'Spring Best', but since the variety name is enclosed in single quotes, and there are additional single quotes within that name, I am not sure if this is the correct variety name.

No.0472.a Bulbophyllum boninense (Ogasawara's shikoran)

This is a perennial herb, growing to a height of 15-20 cm. It is epiphytic. The rhizome is long, bearing pseudobulbs at 3-4 cm intervals at the nodes. The pseudobulbs are 1.3-2 cm long and 0.6-1 cm wide. A single leaf grows at the tip of each pseudobulb; the leaf blade is oblong, 7-12 cm long and 1.8-2.7 cm wide. It is leathery and glossy. It flowers from June to July. Three to five flowers grow at the end of a drooping flower stalk 15-20 cm long, elongated in shape, about 2.5 cm long, pale yellow with a dark reddish-purple spot in the center. The dorsal sepal is broadly ovate, with a short, pointed tip that is semi-curved, about 1 cm long. The lateral sepals are broadly ovate with a blunt tip, fused in the apex, about 3 cm long. The lateral petals have shallowly lobed edges and are about 7 mm long. The labellum is five-shaped, with a joint at the base. The labellum and petals are dark reddish-purple. There is a pair of sickle-shaped white appendages at the tip of the column. It resembles *Shikoran*, but differs in that its rhizome is elongated, hard, and thick, the pseudobulbs are spaced 3-4 cm apart, the lateral sepals are broadly ovate with blunt tips and fused at the ends, and they do not extend long enough to have a dark reddish-purple spot in the center of the flower, and instead fuse at the tips. It is endemic to Japan and is distributed in the Ogasawara Islands, growing epiphytically on rocks and tree trunks.

No. 0474 Cymbidium goeringii

Also known as "mole," this is an evergreen terrestrial species. The pseudobulb is small and ovoid. The leaves have finely serrated edges and grow in clusters of several. The flower stalk is erect, 10-20 cm tall, and its base is enclosed in a membranous sheath. It flowers from March to April. The flower is solitary and pale yellowish-green. The bracts are lanceolate. The sepals are obovate. The lateral petals are the same shape as the sepals but slightly shorter. The labellum is oblong, slightly shorter than the sepals, fleshy, shallowly 3-lobed, and white with purple markings. The lateral lobes are erect, and the central lobe is elliptical with a recurved tip. The column is about 15 mm long. There is considerable variation in flower shape and color depending on the habitat. The capsule is columnar-elliptic. It is distributed in Hokkaido (Okushiri Island), Honshu, Shikoku, Kyushu, the Ogasawara Islands, Korea, China, and Taiwan. It grows in somewhat dry woodlands. Like the Calanthe orchid, it is endangered by human activity and is rare.

No. 0476 Cymbidium dayanum

This is an evergreen perennial herb. The leaves are 30-50 cm long, flexible, and herbaceous. In winter, a 30 cm long inflorescence emerges from the base of the plant, accompanied by membranous sheath-like leaves, bearing white to pale reddish-purple flowers. The perianth segments are about 3 cm long, with a long spot in the center of the inner surface. The Japanese name, Kanpōran, means "winter phoenix orchid," referring to the orchid that blooms in the cold. It is distributed from Assam, India to the Malay Archipelago. A smaller variety of this species grows wild from southern Kyushu to the Ryukyu Islands and is sometimes distinguished as Hetsukaran. It has been in Japan since ancient times and is cultivated to some extent.

No.0478.a Cymbidium cv. (a cultivated variety of the genus Cymbidium).

The group of orchids known as "Cymbidium" in horticulture is generally limited to cultivated varieties of orchids native to Southeast Asia. The original species is likely unknown. They have orchid-like pseudobulbs from which long, slender leaves grow in a basal manner. Flowers are borne singly or in racemes on stems that emerge from the base of the pseudobulbs. The flower stalks are upright, slightly drooping, or drooping and growing long downwards.

No.0478.b Oncidium sphacelatum

This is a perennial plant belonging to the Oncidium or Oncidium genus. It grows to a height of 10-70 cm, is an epiphytic plant, and occasionally grows as a lithophyte. It flowers from September to October. In spring, it produces 10-50 flowers on short branches extending horizontally and vertically from the leaf sheath of the mature rhizoid, reaching up to 180 cm in length. The calyx and lateral petals are almost identical in shape, narrower and smaller than the labellum. It produces showy flowers with a weak fragrance. The labellum is large and spreads out, making up the majority of the flower. The fruit is a capsule. The fruit does not split open, and the seeds are released through the gaps. It is distributed in Central and South America, specifically Mexico, Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica, and Venezuela, at altitudes below 1000m. The following specimens are cut flowers sold in Japanese horticulture, and therefore may be different species or cultivars of unknown origin.

No.0487.a Jade Orchid (Vanda coerulea)

Also known as Vanda. Stems are 5–23 cm long and 0.8–1.5 cm in diameter (Flora of China). Leaf blades are (7–)14–18 cm long and 1.3–2 (–3) cm wide, thick and leathery, with an unevenly shallow 2-lobed tip. Inflorescences are borne in groups of 1–3, 20–42 cm long, with sparsely arranged (4–)6–14 flowers. They bear large, long blue, mosaic-patterned flowers. The peduncle is 16–22 cm long. The inflorescence axis is weakly zigzag and 9–28 cm long. The flower bracts are broadly ovate, 8–11 mm long and 5– mm wide, with an obtuse to acute tip. The flowers are thin in texture, open wide, and 6–9 cm in diameter. The pedicels and ovaries are white or bluish, 45–60 mm long. The sepals and petals are sky blue and have a mosaic pattern. The sepals are equiform, broadly obovate, with a narrowing base and a short claw-like structure, and a rounded apex. The petals are elliptic-obovate, with a narrowing base and a short claw-like structure, and a rounded apex. The labellum is sky blue, shorter than the sepals, fleshy, and has a spur. The lateral lobes are erect, narrowly sickle-shaped, white on the inside with yellow spots, and nearly acute at the apex. The central lobe is dark blue, tongue-shaped, with a pair of calli at the base, a truncate and concave apex, and the disc (the area between the lateral lobes of the lower half of the labellum) has three longitudinal ridges. The spur is short tubular, slightly conical, 5-7 mm long and 2-3 mm wide, with an obtuse apex. It mainly flowers from October to November and is distributed in northeastern India, Myanmar, and northern Thailand, inhabiting open forests and tree trunks along rivers. There are many horticultural varieties, and various hybrid species with red and yellow flowers have been created.

No. 0488 Phalaenopsis aphrodite

This is a monopodial orchid that grows on trees and other plants. It is an epiphytic orchid. The stem is very short and erect, with about four leaves densely packed at the top and numerous roots emerging from the bottom. The roots are thick and grow well. The leaves are arranged in two rows, overlapping each other, and are oval to oblong in shape with a green surface. The flower stalk grows from the side of the stem, ascending obliquely and drooping at the tip, reaching a length of 50-80 cm, sometimes branching. It bears a dozen or so flowers near the tip. The flowers are white, about 7 cm in diameter, with broad lateral petals, giving the entire flower a round appearance. The labellum is yellowish with reddish markings. The tip of the labellum protrudes to the left and right, forming a tendril-like structure. It is evergreen and performs CAM photosynthesis. It is distributed in Southeast Asia, including the Philippines, southern China, and Taiwan, as well as tropical and subtropical regions, growing epiphytically on trees in hot, humid, and high-altitude areas such as tropical rainforests, and thrives in well-ventilated environments. It is very popular as a high-end potted plant and cut flower.

There are differences between Phalaenopsis orchids and other similar species! We'll explain how to distinguish between them! Why are they so popular? What's their history? Did the flowers attach pollen clumps to the backs of insects?! But the species is unknown?

Phalaenopsis orchids are very popular in Japan as high-end potted plants and cut flowers. They are the number one orchid species in terms of both production volume and value. However, they are also known as "Phalaenopsis," which can be confusing. Biologically, the terms refer to different species, and Phalaenopsis orchids are actually "Phalae..."

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References

Hayakawa, M. & Sueji, K. 2017. Morphological variation and classification of Spiranthes sinensis. Journal of Plant Science 51(4): 115-117. ISSN: 0289-8233, https://da.lib.kobe-u.ac.jp/da/kernel/90005098/

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Odoux, E., & Grisoni, M. 2010. Vanilla, Medicinal and Aromatic Plants – Industrial Profiles. CRC Press. 420pp. ISBN: 9781420083385

Tsukamoto, Yotaro. 1994. Encyclopedia of Horticultural Plants, Compact Edition. Shogakukan, Tokyo. 3710pp. ISBN: 9784093051118

The Colchicaceae family consists of perennial herbs. They have corms or rhizomes. Leaves are alternate, opposite, or whorled, and may be clustered at the base of the stem. Flowers are solitary or borne in racemes or cymes, showing great diversity. They usually bear bisexual flowers. The perianth segments are free or fused, numbering six in number. The ovary is superior. Many species have capsules, but the genus *Colchicum* has berries. There are 15 genera and approximately 275 species worldwide, with many found in southern Africa and distributed in tropical to temperate regions excluding Central and South America. In Japan, there is one genus, *Colchicum*, and four species. *Colchicum* has berries and does not have bulbs, but in the APG system, it is a family consisting of only one genus.

This article provides a comprehensive, illustrated guide to plants belonging to the Colchicaceae family.

The basic information is based on Tsukamoto (1994) and the Kanagawa Prefectural Flora Survey Association (2018). Photographs are replaced as better ones become available. While the identifications are made by the author, please note that they may be changed without notice if misidentifications are found.

No.0314 Colchicum autumnale

This perennial plant produces 1 to 4 pale purplish-pink flowers in early autumn, reaching a height of 15 to 20 cm. The anthers are yellow, the pistil is white, and the leaves are lanceolate, 20 to 30 cm long, appearing in spring. It has been cultivated as a medicinal plant since ancient times, and the highly potent alkaloid colchicine is obtained from the dried corms and seeds. Colchicine has been used since ancient times as a miraculous remedy for gout. Because colchicine has a chromosome-duplicating effect, it is often used in plant breeding. It is distributed in Europe and North Africa and grows in pastures.

No.0315 Disporum smilacinum

A perennial herb. The stems are usually unbranched and grow to a height of 15-40 cm. In April and May, it produces white flowers that face sideways or diagonally downwards. The perianth segments are 1-1.5 cm long. It is distributed in Hokkaido, Honshu, Shikoku, Kyushu, Korea, and China. The branched variety is called Edauchichigoyuri var. ramosum.

No.0317 Disporum sessile

This is a perennial herb, growing to a height of 30-60 cm. Stems range from simple to several-branched. The leaves have three prominent veins and vary considerably in shape, from broad to narrow. In April and May, it produces tubular, greenish-white, drooping flowers. The perianth segments are green in the upper half and white in the lower half. The fruit is spherical, about 1 cm in diameter, and ripens to black. It is distributed in Hokkaido, Honshu, Shikoku, Kyushu, Korea, China, and Sakhalin. It grows in forests from coastal areas to mountainous regions.

No.0317.1 Disporum sessile f. stenophyllum

This variety has leaf blades narrower than those of *Disporum sessile*, which typically have a leaf blade width of 2-3 cm. It is found in southern Kanto, Tokai, Shikoku, and Kyushu, but is particularly common in the Fossa Magna region. Intermediate forms between this variety and *Disporum sessile* (in the strict sense) also exist. Leaf blade measurements for the following individuals have not been taken.

References

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Tsukamoto, Yotaro. 1994. Encyclopedia of Horticultural Plants, Compact Edition. Shogakukan, Tokyo. 3710pp. ISBN: 9784093051118

The egret orchid (Habenaria radiata) is a perennial plant that inhabits slightly damp areas and is a popular choice for gardeners. Unfortunately, due to the decline of its wetland habitat and illegal harvesting, it is listed as near threatened on the Ministry of the Environment's Red List. There are many closely related species, and many species bear the name "egret orchid," but very few other species have a labellum that is flat and protrudes laterally like an egret's, making it easy to distinguish. The egret orchid is conspicuous , so one might think it has been known since ancient times, but the oldest record is thought to be in the "Nippo Jisho" (Japanese-Portuguese Dictionary), compiled between 1603 and 1604. However, it seems to have been known even before that, and the "Egret Orchid Legend" associated with Setagaya Castle is a famous tragic story. Do you know what kinds of insects visit the lovely egret orchid flower? In addition to the nocturnal hawk moth, which has been pointed out before, skipper butterflies also visit during the day. Even more surprisingly, recent research has shown that tiny insects called thrips also play an auxiliary role in ensuring pollination. The fruit is a capsule and the seeds are dispersed by wind, but in orchids, including Habenaria radiata, protocorms and orchid mycorrhizal fungi are essential for seed germination. This article will explain the history, physiology, and pollination ecology of Habenaria radiata.

Near Threatened Species that Inhabit Wetlands

Habenaria radiata (synonym: Pecteilis radiata), also known as egret orchid, is a perennial plant distributed in the Korean Peninsula, the Russian Far East, eastern China, and Japan (Hokkaido, Honshu, Shikoku, and Kyushu), and inhabits slightly damp areas (Enomoto and Sakamoto, 2022).

It belongs to the genus *Hymenophyllum* in the orchid family, and due to the reduction of its wetland habitat caused by excessive land development and illegal harvesting, it is listed as Near Threatened (NT) on the Ministry of the Environment's Red List, and in many prefectures it has been designated as either Extinct or Near Threatened (Wildlife Survey Association/Envision Environmental Conservation Office, 2022).

[Seed Plant Encyclopedia #074] What are the types of orchids? Photo list

Orchids (Orchidaceae) are terrestrial, epiphytic, lithophytic, mycoheterotrophic perennial herbs. Stems are monopodial (single-stemmed) or sympodial (compound-stemmed) with long stems, or they have rhizomes or enlarged pseudobulbs. Leaves are mostly flattened, with a tubular sheath at the base, sometimes reduced to scales. Flowers are...

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What species resembles the egret orchid? What are the differences between the egret orchid and the large egret orchid?

The genus Habenaria, to which the egret orchid belongs, is quite large, and many species are known in Japan.

The species of Habenaria in the genus Habenaria that have "sagisou" in their name include Habenaria dentata, Habenaria pantlingiana, Habenaria ciliolaris, Habenaria petelotii, Habenaria polytricha, and Habenaria stenopetala.

In addition, several species other than those in the genus *Habenaria* are known to have "sagi-sou" (a type of orchid) in their name.

However, with the exception of the Great Egret Orchid, none of the other flowers have a flat, wide, and spreading labellum located below the corolla, so the only similarity is the name.

The only difference between the two is that the Great Egret Orchid (Habenaria radiata) resembles the Egret Orchid (Habenaria radiata), but in the Egret Orchid, the two petals (lateral petals) positioned at the top of the flower extend forward, while in the Great Egret Orchid, they extend significantly to the sides. Furthermore, the Great Egret Orchid has significantly fewer lobes on its labellum. Therefore, it is unlikely that you would mistake them for each other.

Surprisingly, the historical records are relatively recent? What is the legend of the egret flower?

It is sometimes cultivated as an ornamental plant in the wild, so it may have a long history with the Japanese people.

However, the first appearance of the name "Sagisou" (Habenaria radiata) in literature is surprisingly recent. While descriptions in "Kadan Chikinsho" (Ito, 1695), a book on horticulture from the Edo period, are widely available on the internet, it is known that the name also appears in the "Nippo Jisho," a dictionary of Japanese words explained in Portuguese, which was compiled in 1603-1604 (Isono, 2004; 2009).

The egret orchid has been chosen as the symbolic flower of Setagaya Ward in Tokyo and Himeji City in Hyogo Prefecture.

The reason why the egret flower was chosen as the official flower of Setagaya Ward in Tokyo is due to a legend known as the "Legend of the Egret Flower," which is associated with Setagaya Castle.

Tokiwa-hime, the beloved daughter of Ohira Dewa-no-kami, the lord of Okusawa Castle, was chosen as the tenth concubine by Kira Yoriyasu, the seventh lord of Setagaya Castle, and became his favorite, bearing him a child. However, Yoriyasu's other nine concubines, jealous of this, plotted against Tokiwa-hime, falsely accused her of a crime, and she was eventually captured by pursuers in Kamiuma and forced to commit suicide. Before being driven out of Setagaya Castle, Tokiwa-hime entrusted a letter to Ohira Dewa-no-kami, asking for help, to a white heron attached to its leg. However, the rain made the letter too heavy for the heron's leg, and it succumbed to exhaustion and died near Okusawa Castle. The heron's remains were discovered by villagers nearby and given a respectful burial. The following summer, beautiful flowers bloomed all at once at the spot where the heron was buried, resembling the heron in flight. People named this flower "Sagisou" (heron flower) in remembrance of Princess Tokiwa's fate.

"Okusawa Castle" in the Japanese Wikipedia and "Setagaya Castle Town History, Revised Edition"

It is merely a legend, and the details seem to differ depending on the historical source. Kira Yoriyasu's birth year is unknown, but he died in 1562, which is older than the *Nippo Jisho* (Japanese-Portuguese Dictionary). Therefore, there is a non-zero possibility that the name of the egret flower is somehow related to Tokiwa-hime, but it seems likely that the egret flower was recognized long before this legend. Nevertheless, it is certainly a romantic legend.

What is the structure of the flower that resembles a heron?

The flower resembles a heron, as you may know. It blooms in July and August (Satomi et al., 1982). As it belongs to the orchid family, it has a distinctive "orchid-shaped corolla," consisting of three sepals and three petals. Originally, it had three petals and three sepals, but they are cleverly combined (Shimizu, 2001). The three sepals support the three petals from behind.

Of the three petals, the lowermost one, the labellum, is large and deeply three-lobed, divided into a central lobe and two lateral lobes. The central lobe is lanceolate, while the lateral lobes on either side are obliquely fan-shaped, opening laterally, and their edges are finely divided. The Japanese name comes from the fact that the open appearance of this labellum resembles a white heron spreading its wings (Takamura, 2005).

Furthermore, of the three petals, the two upper petals, which are lateral petals, are white and have a distorted oval shape, enclosing the column, which is the fused structure of the stamens and pistil.

The flower has a hole in its center, connected to a 3-4 cm long, drooping spur. The tip gradually thickens, and nectar accumulates at this end. This suggests that insects with considerably long mouthparts are likely to visit the flower.

Sphinx moths are visiting the flowers of the egret orchid!?

So, what kinds of insects visit flowers with such long spurs?

Records published by numerous Japanese research groups indicate that members of the Sphingidae family visit the area (Ihara, 2013; Shigeta & Suetsugu, 2020; Tachibana et al., 2020). This tendency has also been widely observed in members of the Habenaria genus, to which the Habenaria orchid belongs (Ikeuchi et al., 2015; Shigeta & Suetsugu, 2020).

Specifically, there are records of the small hawk moth (Theretra japonica) (Shigeta & Suetsugu, 2020) and the striped hawk moth (Theretra oldenlandiae) (Tachibana et al., 2020). Both are common hawk moth species in Japan, and both are nocturnal moths with very long proboscises.

At night, these moths visit the Habenaria radiata flowers, using the labellum as a guide. The moths insert their long proboscis into the hole in the center of the flower and try to suck the nectar stored in the spur. The spur is just the right length, longer than the proboscis, so the moth can just barely suck the nectar. As the moth tries to thrust its proboscis as far as possible, it comes into contact with the column at the top of the flower's opening. When it comes into contact, pollen masses with mucous suction cups attached to the proboscis and compound eyes stick to it, and if it has pollen masses from another individual, pollination occurs.

While hawk moths and egret orchids don't have a one-to-one relationship, it seems that the exquisitely balanced length of their proboscis and spur is the result of evolution through various interactions.

Flowers exhibit a "pollination syndrome," where their shape tends to be influenced to some extent by the type of pollinator that carries their pollen. Sphinx moth-pollinated flowers are known to exhibit a whitish coloration, bloom at night, have large, conspicuous tubular corollas, and emit a strong, sweet fragrance from evening to morning. The egret orchid is thought to fulfill these characteristics well, except for the scent.

Butterflies had even come by lunchtime!?

However, moths are not the only creatures that visit this flower. Other studies conducted through direct observation and photography in various locations have shown that skipper butterflies also visit during the daytime (Kimura, 1980; Suetsugu & Tanaka, 2014; Ikeuchi et al. 2015).

Specifically, these are the species *Parnara guttata*, *Parnara guttata*, and *Parnara guttata*, all of which are relatively common in Japan. *Parnara guttata*, in particular, can be seen even in urban areas.

Butterflies have remarkably long proboscises and are often thought to be nectar robberies, but it has been confirmed that pollen masses attach to the butterfly's body through the same process as hawk moths (Kimura, 1980; Suetsugu & Tanaka, 2014).

This phenomenon has so far been confirmed in Fukuoka and Nara prefectures, so it's unclear if it will occur everywhere. However, considering that the egret orchid blooms even during the daytime, it's highly likely that it will be observed more widely.

It is strange that butterflies are also attracted to plants that have characteristics specifically suited to hawk moths, but butterflies tend to be attracted to plants like Trachelospermum asiaticum and Clerodendrum trichotomum as well, so perhaps the tactic of using different plants during the day and night is surprisingly common (Miyake et al., 1998).

What are the differences between Trachelospermum asiaticum, Trachelospermum asiaticum, and Trachelospermum asiaticum? We'll explain how to distinguish between similar species! Is it historically true that the name originates from "Fujiwara no Teika"? What is the ecological reason why they bloom and emit a fragrance in the evening?

Trachelospermum asiaticum and Trachelospermum asiaticum are climbing plants that can be widely found in Japan, from forests to urban areas, including cultivated varieties. They can be distinguished by the hairs on the underside of their leaves and the length of their flower tubes. They have been widely known in Japan since the time of the writing of the Kojiki, and their current names are derived from "fuji" (wisteria)...

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What are the differences between Clerodendrum trichotomum, Clerodendrum sibiricum, Clerodendrum humile, and Clerodendrum sibiricum? We'll explain how to distinguish between similar species! Do the leaves really smell? Do the flowers rely on both moths and butterflies for pollination?

Clerodendrum trichotomum, named for the foul odor of its leaves, is a tree distributed in East Asia. Several varieties and closely related species are known. These can be distinguished mainly by the length of the stamens on the flowers and the amount and shape of the hairs on the leaves. While the leaves do have an odor, not everyone finds it smelly; some people may find it unpleasant...

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Hidden visitors: tiny insects called thrips?

In addition to the two groups mentioned above, more recent research has revealed some interesting facts (Shigeta & Suetsugu, 2020).

It turns out that thrips, tiny insects that come to feed on pollen, also play a role in pollination! Specifically, the species is Frankliniella intonsa.

Because thrips are very small, a single one doesn't carry much pollen. However, it's known that they visit flowers in countless numbers at certain times of the year, and I've seen them quite often myself.

Thrips become adults in one to two weeks, and since they go through several generations during a single flowering season, a large number of individuals are born.

Therefore, they contribute significantly as pollinators, and there are records showing that they contribute to the pollination of one-quarter of all seeds produced by the egret orchid.

However, hearing that, you might think it would be more efficient to rely entirely on thrips for pollination, right?

However, relying on thrips for pollination also has its drawbacks.

Thrips are thought to promote self-pollination because they move pollen around within flowers in order to eat it. However, self-pollination can make seed production difficult and cause problems in the plant's growth process. Therefore, it's best to use them only as a supplementary tool.

Since the egret orchid relies on different insects during the day and night, and uses thrips as a supplement, it may be capable of more flexible pollination than we realize!

The fruit is a capsule, and the seeds are dispersed by wind.

After pollination, the flowers of the Habenaria radiata develop into fruits. The fruits are capsules, common to all orchids. Like many orchids, the seeds are dispersed by wind, and the capsules are densely packed with tiny seeds (Miura et al., 2019). It is believed that a single capsule contains tens of thousands to hundreds of thousands of seeds, and when it ripens, gaps form, allowing countless tiny seeds to spill out and be dispersed by a weak breeze.

Considering the symbiotic relationship with mycorrhizal fungi, long-distance travel carries risks, so they may not travel very long distances.

Protocorms and orchid mycorrhizal fungi are essential for seeds!

Do you know what nutrients plant seeds use to grow?

For example, grasses store energy sources in their endosperm, and legumes store them in their cotyledons. You may have learned this in childhood. However, orchids have no endosperm, and most species lack cotyledons as well (Yeung, 2017)!

The seeds of orchids, including the Habenaria radiata, first swell into a spherical shape after germination. This is called a "protocorm." In this stage, they live in symbiosis with fungi called "orchid mycorrhizal fungi," which inhabit the plant's roots.

The orchid mycorrhizal fungi utilize the cellulose of orchid plants by hydrolyzing it, and the orchid plants obtain an energy source by receiving carbon from them, creating a win-win relationship (Yamato and Tanigame, 2009). However, since hydrolyzing cellulose means that the plant's body is being broken down, it's unclear whether it's truly a 100% win-win situation.

This means that the egret orchid has a stage where it relies on other organisms for energy (heterotrophy) before it transitions to the stage where it obtains its own energy source through photosynthesis (autotrophy).

Orchid species have evolved to specialize in obtaining energy through symbiosis with orchid mycorrhizal fungi, resulting in the loss of endosperm and cotyledons (Yamato and Tanigame, 2009; Yeung, 2017).

While many other symbiotic relationships between mycorrhizal fungi and plants are known, this is quite unique because, generally speaking, the mycorrhizal fungi obtain their energy source from the plant.

This type of relationship has been observed in many orchid species, and it is established between specific orchids and specific orchid mycorrhizal fungi.

On the other hand, conversely, this means that orchids cannot grow without orchid mycorrhizal fungi. This is thought to be the reason for their small population size, low tolerance to environmental changes, and difficulty in cultivation (Yamato and Tanigame, 2009).

This is also a challenge in the conservation of Habenaria radiata, and attempts have been made to artificially induce germination by inoculating with orchid mycorrhizal fungi (Enomoto and Sakamoto, 2022) or by using artificial endosperm (Mitsuishi et al., 2021).

But why do orchids rely on symbiosis with orchid mycorrhizal fungi in the first place?

Although I couldn't find any papers that explicitly state this, based on what I've considered so far, my conclusion is that because the parent plant doesn't need to store energy sources in the endosperm and cotyledons for the seed to develop initially, it has an advantage over other plants in certain environments, such as the presence of fungi, allowing for stable offspring development. On the other hand, it's likely that a disadvantage is that it may become unable to produce offspring if the environment changes.

References

Enomoto, Hiroyuki & Sakamoto, Hideki. 2022. Records of habitats and population size (2017-2021) of * Pecteilis radiata (Thunb.) Raf.* confirmed in Fukui Prefecture. *Ciconia* 25: 97-105. ISSN: 1342-0933, https://fncc.pref.fukui.lg.jp/wp-content/uploads/2022/03/Ciconia_vol25_15.pdf

Hitomi, Teruhito. 2004. Historical Tales of Setagaya Castle Town, Revised Edition. Hitomi, Teruhito, Tokyo. 171pp.

Ihara, Hideyuki. 2013. Sphinx moths carrying pollen masses of Habenaria radiata. Nature Study 59(9): 6, 12. ISSN: 0466-6089, http://www.omnh.net/ns_online/html/v59/59-09_004.html

Ikeuchi, Y., Suetsugu, K., & Sumikawa, H. 2015. Diurnal skipper Pelopidas mathias (Lepidoptera: Hesperiidae) pollinates Habenaria radiata (Orchidaceae). Entomological News 125(1): 7-11. ISSN: 0013-872X, https://doi.org/10.3157/021.125.0103

Ito, Ihei Sannojō. 1695. Kadan Chikinshō. ISBN: 9784540950377, https://doi.org/10.11501/1209343

Isono, Naohide. 2004. "Sketch of Plants and Trees" by Kano Shigekata. Keio University Hiyoshi Journal of Natural Science 36: 1-14. ISSN: 0911-7237, https://koara.lib.keio.ac.jp/xoonips/modules/xoonips/detail.php?koara_id=AN10079809-20040930-0001

Isono, Naohide. 2009. List of First Encounters of Plant Names by Source. Keio University Hiyoshi Journal of Natural Science 45: 69-94. ISSN: 0911-7237, https://koara.lib.keio.ac.jp/xoonips/modules/xoonips/detail.php?koara_id=AN10079809-20090331-0069

Kimura, Naho. 1980. Observation and cultivation of Habenaria radiata. New Science Co., Ltd., Tokyo. 96pp. ISBN: 9784821600632

Mitsuishi, T., Dono, H., Furukawa, S., and Takitani, S. 2021. Development of artificial seeds using slightly acidic electrolyzed water. Kyousei no Hiroba 16: 128-129. ISSN: 1881-2147, https://www.hitohaku.jp/publication/book/kyousei16-p128.pdf

Miura, C., Saisho, M., Yagame, T., Yamato, M., & Kaminaka, H. 2019. Bletilla striata (Orchidaceae) seed coat restricts the invasion of fungal hyphae at the initial stage of fungal colonization. Plants 8(8): 280. https://doi.org/10.3390/plants8080280

Miyake, T., Yamaoka, R., & Yahara, T. 1998. Floral scents of hawkmoth-pollinated flowers in Japan. Journal of Plant Research 111(2): 199-205. ISSN: 0918-9440, https://doi.org/10.1007/BF02512170

Satomi, Nobuo; Satake, Yoshisuke; Oi, Tsugusaburo; Kitamura, Shiro; Watari, Shunji; and Tominari, Tadao. 1982. Wild Plants of Japan (New Edition, Herbaceous Plants 1, Monocotyledons). Heibonsha, Tokyo. 305pp. ISBN: 9784582535013

Shigeta, K., & Suetsugu, K. 2020. Contribution of thrips to seed production in Habenaria radiata, an orchid morphologically adapted to hawkmoths. Journal of Plant Research 133(4): 499-506. ISSN: 0918-9440, https://doi.org/10.1007/s10265-020-01205-z

Shimizu, Takemi. 2001. Illustrated Dictionary of Botanical Terms. Yasaka Shobo, Tokyo. xii, 323pp. ISBN: 9784896944792

Suetsugu, K., & Tanaka, K. 2014. Diurnal butterfly pollination in the orchid Habenaria radiata. Entomological Science 17(4): 443-445. ISSN: 1343-8786, https://doi.org/10.1111/ens.12081

Tachibana, T., Nishikawa, Y., Kubo, N., & Takeda, S. 2020. Morphological and Genetic Diversities of Habenaria radiata (Orchidaceae) in the Kinki Area, Japan. International Journal of Molecular Sciences 22(1): 311. ISSN: 1422-0067, https://doi.org/10.3390/ijms22010311

Takamura, Tadahiko. 2005. A Illustrated Guide to Seasonal Wildflowers and Mountain Plants, Searchable by Color, Size, and Flowering Order. Nihon Bungeisha, Tokyo. 367pp. ISBN: 9784537203677

Yamato, Masahide & Tanigame, Takahiro. 2009. Symbiosis between orchids and fungi. Bulletin of the Mycological Society of Japan 50(1): 21-42. ISSN: 0029-0289, https://doi.org/10.18962/jjom.jjom.H20-02

Wildlife Survey Association / Envision Environmental Conservation Office. June 4, 2022. Japan Red Data Search System. http://jpnrdb.com/

Yeung, EC 2017. A perspective on orchid seed and protocorm development. Botanical Studies 58(1): 1-14. ISSN: 1817-406X, https://doi.org/10.1186/s40529-017-0188-4

Bletilla striata is a perennial plant that is naturally distributed from Honshu to Okinawa in Japan, but wild specimens are classified as near-threatened. On the other hand, it is also popular as an ornamental plant and can be seen in almost any town. It was once thought that the wild population in Japan was an escaped cultivated plant, but now the view that it is naturally distributed is generally accepted. A similar species is Orchid japonica. It was once used in China as a hemostatic agent to stop pulmonary hemorrhage and cough up blood, and during the Edo period, it became widely known for its ornamental and medicinal properties. Bletilla striata has a complex structure with a "corolla shaped like an orchid," which is common to the orchid family, but its appearance is not particularly unique among orchids. However, Bletilla striata has one major difference from other orchids: it does not secrete nectar. It deceives insects by mimicking nectar-producing flowers, and is pollinated by a small number of bees. However, if insects learn to do this, pollination may become impossible. Recent research suggests that, as a solution, the plant may be utilizing not only bees that simply seek rewards from flowers, but also male bees that come looking for female bees that are (deceived) to visit the flowers in search of nectar. The fruit is a capsule and is dispersed by wind. This article will explain the history, pollination ecology, and seed dispersal of the Bletilla striata.

Endangered species seen in town

Bletilla striata, also known as the purple orchid, is a perennial herb distributed in China, Korea, Taiwan, and from Honshu to Okinawa in Japan, growing on sunny, moist slopes (Kadota et al., 2013; Ogawa & Miyake, 2020).

It belongs to the genus Bletilla in the orchid family, and its variety, Bletilla striata f. gebina, has white flowers.

[Seed Plant Encyclopedia #074] What are the types of orchids? Photo list

Orchids (Orchidaceae) are terrestrial, epiphytic, lithophytic, mycoheterotrophic perennial herbs. Stems are monopodial (single-stemmed) or sympodial (compound-stemmed) with long stems, or they have rhizomes or enlarged pseudobulbs. Leaves are mostly flattened, with a tubular sheath at the base, sometimes reduced to scales. Flowers are...

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In Japan, wild specimens are classified as near-threatened, but they can grow in a wide range of conditions depending on sunlight, soil type, and water, and are popular as ornamental plants because they can be easily propagated by division (Kawahara, 2008). They seem to be found in almost every town. The rhizome consists of a series of enlarged, flattened, spherical corms resembling a snail.

What are some species similar to Bletilla striata? What are the differences between Bletilla striata and Orchidaria japonica?

You probably won't see many species that resemble Bletilla striata. You can assume that almost all of the plants you see growing in town are Bletilla striata.

However, a closely related species in the same genus is known to be Bletilla formosana.

The Japanese orchid (Amanara) is a terrestrial orchid that grows naturally in the highlands (600-3100m above sea level) of the Ryukyu Islands in Japan, southern China, and Taiwan. It is sometimes seen as a cultivated plant, but it is rarely encountered.

Compared to Bletilla striata, Bletilla striata has a more dramatically wavy lip petal with reddish-purple spots, and its leaves are narrower and smaller (Wu et al., 2009), so it is unlikely that they will be confused.

Savior of pulmonary tuberculosis

While some believe that the wild population in Japan originated from escaped cultivated plants, recent field guides suggest that it is likely a native species (Kanagawa Prefecture Flora Survey Association, 2018). It is said to appear under the name "Kei" in the Manyoshu, a collection of Japanese poetry from the Nara period, indicating that it was recognized at least from that time (Kawahara, 2008).

In China, it is mentioned in the " Shennong Ben Cao Jing," a Chinese medical text compiled during the Later Han and Three Kingdoms periods (Uchida Wakan Yakuhin, 2023). In ancient times, the corm of the Bletilla striata was used as a crude drug called "Byakukyu," a name derived from its color, and was used as a hemostatic agent to stop pulmonary hemorrhage and cough up blood (Torigoe, 2005; Fan et al., 2023). It seems to have attracted particular attention for its use in stopping coughing up blood in pulmonary tuberculosis. Later, in Japan, it became widely known for horticultural and medicinal purposes during the Edo period (Kobayashi, 1986).

Typical flower shape of the orchid family

The flowers bloom in spring, from April to May, and grow in clusters of several large, reddish-purple blossoms (Kadota et al., 2013). This is the origin of the name "Shiran" (purple orchid). It's very simple, isn't it?

It has a distinctive corolla shape, known as "orchid-shaped corolla," which is common to all plants in the orchid family. It consists of three sepals and three petals, which are cleverly combined from what were originally three petals and three sepals (Shimizu, 2001).

The three sepals, one at the top and two at the bottom, are the same color as the petals and support the flower's structure while, along with the petals, attracting insects from afar. The parts extending diagonally upwards are made up of two "lateral petals," and the complex-looking structure in the center is a modified petal called the "labellum."

The labellum has folds and is composed of the "central lobe," which is the most prominent part, and the "lateral lobes" that surround it. Above the central lobe is a structure called the "column," which is a fused structure of stamens and pistil.

Insects that come to a flower are drawn to the entire flower, reaching the very conspicuous central lobe, where they perch on the folds and enter the flower, supported by the lateral lobes, and then make contact with the column on their backs to transfer pollen. The folds of the central lobe, in particular, are thought to be visually important to insects (Sugiura, 1995).

A flower that deceives bees

Up to this point, the pollination process is almost the same as that of other orchid species. However, the Bletilla striata has one major difference from other orchid species: it does not secrete nectar (Sugiura, 1995; Ogawa & Miyake, 2020)! This means that it mimics other nectar-producing flowers to deceive insects and get them to carry its pollen. This type of mimicry is called "generalized food-deceptive" (Ogawa & Miyake, 2020). What's interesting about this mimicry is that it's not mimicking a specific target, but rather it simply thinks of itself as "somewhat an ordinary flower." In other words, it might be fair to say that the abstract concept of "flower" that humans sometimes use is also observed in the natural world.

A wide variety of insects visit the orchid, including many species of bees, butterflies and moths, and flies (Sugiura, 1995; Ogawa & Miyake, 2020). However, only a select few types of bees, such as the Japanese honeybee (Hymenoptera japonica), the white-striped honeybee (Hymenoptera leucobryum), and the European honeybee, contribute to pollination. Therefore, it can be thought that the orchid is primarily trying to attract bees of a relatively medium size.

If you can no longer fool them the normal way, will you use the love of male bees?

However, like many flowers that deceive insects, this strategy has a major problem: bees memorize the shape and color of the flower and gradually stop visiting it. This is especially true for Bletilla striata, which often bloom in dense clusters, making it even more likely for bees to remember its shape. Yet, Bletilla striata flowers are still successfully pollinated. Why is that?

Recent research suggests that the reason for this is that not only insects that come seeking rewards from flowers, but also male bees that come looking for female bees that are (deceived ) to visit the flowers in search of nectar, are important factors (Ogawa & Miyake, 2020).

Male bees sometimes lie in wait near flowers where female bees are likely to appear in order to mate with them. At this time, the male bees may occasionally enter the flowers to (presumably) satisfy their hunger. The hypothesis is that because the male bees are so preoccupied with finding females that they do not have time to learn, they regularly visit the flowers of the Bletilla striata, resulting in successful pollination. This method of pollination is called "rendezvous attraction." In fact, it has been observed that male bees patrol around Bletilla striata and, even after realizing that the flowers are false flowers that do not secrete nectar, they still occupy the area (Sugiura, 1995).

However, it remains to be seen whether male bees truly don't remember the shape and color of flowers, or if there's another reason. Do male bees really have such poor memories? Nevertheless, it seems certain that the Bletilla striata employs a unique strategy among orchids!

Incidentally, there is also a variety called *Shirobana-shiran* with white flowers, but this variety has not been covered in the above-mentioned research, so it is intriguing to wonder what the reason for its appearance is.

The fruit is a capsule, and the seeds are dispersed by wind.

The fruit of Bletilla striata is a capsule less than 3.4 cm in length (Wu et al., 2009).

Like many orchid species, the seeds are dispersed by wind, with the capsules densely packed with tiny seeds (Miura et al., 2019). It is believed that a single capsule contains tens of thousands to hundreds of thousands of seeds, and as the fruit ripens, gaps form, allowing countless tiny seeds to spill out and be dispersed by a weak breeze.

Protocorms and orchid mycorrhizal fungi are essential for seeds!

The seeds of orchids, including Bletilla striata, have some unique characteristics.

Do you know what nutrients plant seeds use to grow?

For example, grasses store energy sources in their endosperm, and legumes store them in their cotyledons. You may have learned this in childhood. However, orchids have no endosperm, and most species lack cotyledons as well (Yeung, 2017)!

The seeds of orchids, including Bletilla striata, first swell into a spherical shape after germination. This is called a "protocorm." In this stage, they live in symbiosis with fungi called "orchid mycorrhizal fungi," which invade the plant's roots. In Bletilla striata, the fungus Tulasnella sp. is known to be the symbiotic fungus (Miura et al., 2019).

The orchid mycorrhizal fungi utilize the cellulose of orchid plants by hydrolyzing it, and the orchid plants obtain an energy source by receiving carbon from them, creating a win-win relationship (Yamato and Tanigame, 2009). However, since hydrolyzing cellulose means that the plant's body is being broken down, it's unclear whether it's truly a 100% win-win situation.

This means that Bletilla striata has a stage where it relies on other organisms for energy (heterotrophy) before it can transition to the stage where it performs photosynthesis to obtain its own energy source (autotrophy).

Orchid species have evolved to specialize in obtaining energy through symbiosis with orchid mycorrhizal fungi, resulting in the loss of endosperm and cotyledons (Yamato and Tanigame, 2009; Yeung, 2017).

While many other symbiotic relationships between mycorrhizal fungi and plants are known, this is quite unique because, generally speaking, the mycorrhizal fungi obtain their energy source from the plant.

This type of relationship has been observed in many orchid species, and it is established between specific orchids and specific orchid mycorrhizal fungi.

On the other hand, conversely, this means that orchids cannot grow without orchid mycorrhizal fungi. This is thought to be the reason for their small population size, low tolerance to environmental changes, and difficulty in cultivation (Yamato and Tanigame, 2009).

But why do orchids rely on symbiosis with orchid mycorrhizal fungi in the first place?

Although I couldn't find any papers that explicitly state this, based on what I've considered so far, my conclusion is that because the parent plant doesn't need to store energy sources in the endosperm and cotyledons for the seed to develop initially, it has an advantage over other plants in certain environments, such as the presence of fungi, allowing for stable offspring development. On the other hand, it's likely that a disadvantage is that it may become unable to produce offspring if the environment changes.

References

Fan, Y., Zhao, J., Wang, M., Kennelly, EJ, & Long, C. 2023. Ethnopharmacology of Bletilla orchid species: a comprehensive review on ethnobotany, phytochemistry and pharmacology. Medicinal Plant Biology 2(1): 21. https://doi.org/10.48130/MPB-2023-0021

Kadota, Y., Nagata, Y., & Azegami, N. 2013. Flowers Blooming in the Mountains (Revised and Expanded New Edition). Yama-kei Publishers, Tokyo. 616pp. ISBN: 9784635070218

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726, http://flora-kanagawa2.sakura.ne.jp/efloraofkanagawa.html

Kawahara, Katsuyuki. 2008. Plants in the Manyoshu. Nanpo Shinsha, Kagoshima. 216pp. ISBN: 9784861241345

Kobayashi, Masao. 1986. Notes on Folk Medicines (60) Shiran. Tokyo Pharmaceutical Journal 8(5): 19-22. ISSN: 0285-1733, https://www.toyaku.or.jp/improvement/magazine/index.html

Miura, C., Saisho, M., Yagame, T., Yamato, M., & Kaminaka, H. 2019. Bletilla striata (Orchidaceae) seed coat restricts the invasion of fungal hyphae at the initial stage of fungal colonization. Plants 8(8): 280. https://doi.org/10.3390/plants8080280

Ogawa, Y., & Miyake, T. 2020. How do rewardless Bletilla striata flowers attract pollinators to achieve pollination?. Plant Systematics and Evolution 306(5): 1-8. ISSN: 0378-2697, https://doi.org/10.1007/s00606-020-01709-0

Shimizu, Takemi. 2001. Illustrated Dictionary of Botanical Terms. Yasaka Shobo, Tokyo. xii, 323pp. ISBN: 9784896944792

Sugiura, N. 1995. The pollination ecology of Bletilla striata (Orchidaceae). Ecological Research 10(2): 171-177. ISSN: 0912-3814, https://doi.org/10.1007/BF02347939

Torigoe, Yasuyoshi. 2005. The World of Shōsōin Medicines: Exploring the Origins of Japanese Medicine. Heibonsha, 260pp. ISBN: 9784582852967

Uchida Wakanyaku. 2023. Byakukyu (白及 or 白芨). Herbal Medicine Treasure Chest 305. https://www.uchidawakanyaku.co.jp/kampo/tamatebako/shoyaku.html?page=305

Wu, ZY, Raven, PH, & Hong, DY (Eds.). 2009. Flora of China (Vol. 25 Orchidaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis.

Yamato, Masahide & Tanigame, Takahiro. 2009. Symbiosis between orchids and fungi. Bulletin of the Mycological Society of Japan 50(1): 21-42. ISSN: 0029-0289, https://doi.org/10.18962/jjom.jjom.H20-02

Yeung, EC 2017. A perspective on orchid seed and protocorm development. Botanical Studies 58(1): 1-14. ISSN: 1817-406X, https://doi.org/10.1186/s40529-017-0188-4

Portulaca grandiflora and Portulaca triangularis are two species of Portulaca grandiflora that produce pink flowers. Both are found in Japan as invasive species, either as cultivated plants or as escaped individuals. Both species are native to the Americas. These two species can be easily distinguished by many morphological differences, such as the arrangement of the inflorescence, the presence or absence of ridges on the flower axis, the size of the petals, and the shape of the stigma. The pink flowers of Portulaca grandiflora and Portulaca triangularis are very conspicuous, so one might think that many insects visit them, but overseas studies have shown that only a few bees visit Portulaca grandiflora, and no visiting insects were found at all on Portulaca triangularis. It appears that Portulaca grandiflora and Portulaca triangularis self-pollinate to a considerable extent. The alternative name "three o'clock grass" comes from the fact that they bloom around 3 to 4 pm, which is probably to shorten the flowering time, reduce the number of visiting insects, and allow for self-pollination. The fruit is a capsule, and one theory about the origin of the name is that the seeds burst open and scatter. However, only Portulaca grandiflora truly "explodes" its seeds. There are significant differences in seed dispersal methods between Portulaca grandiflora and Portulaca grandiflora. This article will explain the classification, pollination ecology, and seed dispersal of Portulaca grandiflora and Portulaca grandiflora.

Two species of the Portulaca family that produce pink flowers.

Talinum paniculatum, also known as "bomb orchid," is native to North America, Mexico, the West Indies, Central America, and South America. In its native habitat, it grows in a wide range of environments, from humid to dry forests, savannas, desert shrublands, grasslands, coasts, plains, hills, slopes, rocky areas, sand, clay, limestone, sandstone, igneous rocks, and rocky soils and fissures. In Africa and Asia, including Japan, it has been introduced as a horticultural plant for medicinal and ornamental purposes, and has escaped cultivation, sometimes growing along roadsides in urban areas. It is originally a perennial plant, but in Japan it is treated as an annual (Shimizu et al., 2001; Kanagawa Prefecture Flora Survey Association, 2018). Its very long, orange roots, reaching about 80 cm in length, easily root and propagate. In Asia, it has been used in traditional medicine.

Talinum fruticosum (synonym: Talinum triangulare), also known as the triangular burrowing orchid, is a perennial plant native to North America, Mexico, the West Indies, Central America, and South America, growing in pine forests, disturbed areas, and sandy soils (Flora of North America Editorial Committee, 2004). In tropical regions (West Africa, South Asia, and Southeast Asia), it is eaten after being boiled, and in Okinawa, it is also eaten after being boiled and called Brazilian spinach.

While some sources on the internet claim that Portulaca grandiflora is edible in tropical regions, it seems that Portulaca triangularis is more commonly used for food. However, Portulaca grandiflora is also edible.

Both belong to the genus Portulaca in the family Portulaca, and they may be confused with each other because they both have oval to obovate leaves and pink flowers.

What is the difference between Portulaca grandiflora and Portulaca triangularis?

However, Portulaca grandiflora and Portulaca triangularis are fairly clearly distinguishable (Flora of North America Editorial Committee, 2004; Uemura et al., 2015).

In Portulaca oleracea, the inflorescence is a panicle, the rachis is uniformly slender with no ridges, the petals are 6 mm or less (flower diameter about 7 mm), and the three lobes of the stigma are shallowly lobed. In contrast, in Portulaca triangularis, the inflorescence is a raceme or cymose inflorescence, the rachis has triangular ridges as its name suggests, and is clearly thicker at the distal end, the petals are 7 mm or more (flower diameter about 15 mm), and the three lobes of the stigma are deeply lobed and open.

If you check these points, you should be able to see the difference without any problems. You can understand "陵" as a flat part that protrudes from the plant body. The flower stalk refers to the part from where the flower is attached to where it connects to the stem.

Despite the conspicuous appearance of the Portulaca grandiflora flowers, surprisingly few insects were attracted to them!

Portulaca grandiflora flowers from June to September. The petals are five in number, red to pale pink, rarely orange-yellow, and 3-6 mm long. The sepals are deciduous and 2.5-4 mm long. There are approximately 15-20 stamens. The stigma is three-lobed. The pedicel can reach up to 20 mm in length.

The flowering period of Portulaca grandiflora is year-round. The inflorescence is a raceme or cymose. The flowers have persistent sepals, which are lanceolate to ovate, 5-6 mm long. The petals are purplish, pink, or white, sometimes yellow, elliptic to ovate, 7-13 mm long. There are 20-35 stamens. The stigma is 1, 3-lobed. The pedicel is triangular, thicker at the top, and less than 12 mm long.

With flowers this bright pink, it's safe to assume that a lot of insects will come to them.

However, a study in Venezuela, near the native habitat of Portulaca grandiflora, found that only two bees of the family Carangidae, five bees of the family Apidae (mainly stingless bees), two wasps, and one leafcutter bee visited the flowers of Portulaca grandiflora in 20 hours (Valerio & Ramirez, 2003).

In other words, flowers are visited almost exclusively by bees, and even then, the number of bees that do visit is quite small.

This is likely largely due to the fact that it does not secrete nectar, and pollen is the only reward for insects. Furthermore, its small size, lack of scent, and the small number of flowers opening per day indicate that it is not very appealing to insects.

Also, this is just my guess, but perhaps the variety is limited because they are small and the footing is unstable.

In addition, it has been found that the rate of self-pollination is higher.

These results are quite surprising. Why are they doing this?

This study was conducted in secondary forests in urban areas. In such environments, it would be advantageous to maintain highly adapted genotypes. Therefore, self-pollination allows for the direct transmission of genes adapted to urban environments to offspring.

However, adapting to pests, diseases, fungi, and environmental changes requires a certain amount of gene exchange. Therefore, they seem to employ a win-win approach: relying on a small number of bees to minimize cross-pollination.

It might be considered a somewhat ambiguous and extravagant approach. However, it's undoubtedly crucial for survival.

However, the results in environments other than urban areas have not yet been studied.

Furthermore, since they can escape and grow on roadsides in urban areas in Japan, it means they are producing seeds. But what is the ratio of self-pollination to cross-pollination? This point has not yet been investigated and is quite interesting.

Why is it called "three o'clock flower"? Why does it bloom at three o'clock?

The plant *Portulaca japonica* is also known as *Sanjisou* or *Yojisou*.

It is said that this flower was named because it blooms around 3 or 4 p.m.

Why do Portulaca grandiflora flowers bloom around 3-4 pm?

Other plants with short flowering times include Trachelospermum asiaticum and Lonicera japonica, which bloom in the evening. These plants often do this to attract insects that are active after dusk.

However, in the case of Portulaca grandiflora, considering the Venezuelan study mentioned earlier, it seems that there are many diurnal bees, so this reason is unlikely.

It seems no one has studied this, but it is likely that the fact that Portulaca grandiflora primarily self-pollinates significantly limits the number of visiting insects.

In other words, it seems to me that shortening the flowering period reduces the number of insects that visit the flowers.

Are the flowers of the triangular-leaved moss plant useful?

While self-pollination is the primary method for Portulaca oleracea, what about Portulaca triangularis?

Although not its native habitat, a study conducted in Karnataka, southern India, found no records of pollinating insects during a 36-hour observation period (Shivanna, 2019). Preliminary investigations for this study also found no such records.

However, it was pollinated and produced seeds properly. In other words, the triangular moss plant also relied on self-pollination.

Moreover, it can be said that *Portulaca oleracea* is more dependent on self-pollination than *Portulaca oleracea*.

In the survey area, the flowers begin to open along with the stems and leaves around 9:00 AM, and become horizontal around 12:00 PM. Around 2:00 PM, the tips of the stems and leaves curve and fully open. Around 3:00 PM, the petals and involucral bracts begin to close, but no insects visit the flowers until this point. Around 5:00 PM, the petals and involucral bracts are completely closed. Self-pollination occurs inside at this stage.

Because the flowers are only open for 5-6 hours during the day, it is believed that there is a shortage of pollinators.

However, if insect pollinators were truly unnecessary, flowers should have completely degenerated, but that hasn't happened yet.

Therefore, in environments where pollinators are present, it is natural to assume that, like Portulaca grandiflora, it undergoes mixed pollination involving both cross-pollination by visitors and self-pollination through petal closure.

Is it true that the fruit is a capsule and "bursts open"?

Both fruits are capsules.

In Portulaca grandiflora, the capsule is nearly spherical with three ridges, 3-5 mm in diameter. When mature, it splits into three sections. The seeds are black, distorted disc-shaped, and about 0.8 mm long.

In Portulaca japonica, the capsule is nearly spherical, with a diameter of 4-6 mm. The exocarp and endocarp usually do not separate after dehiscence, and the valves are deciduous.

While these two species showed little difference in their floral ecology, their fruit ecology is quite different (Veselova et al., 2012).

Both species have arils (appendages covering the surface of the seed), but in Portulaca oleracea, the arils do not contain extra nutrients and are not attractive to ants. However, in Portulaca triangularis, the arils contain a lot of protein and lipids, and it has been found that ants are attracted to these and carry the seeds away.

In Portulaca grandiflora, the seeds remain inside the fruit for a considerable period, even after ripening. Subsequently, the capsule is broken open by weathering, or by ants attracted to the capsule, causing it to break open and the seeds inside to be dispersed by gravity and wind. However, although the authors of this paper state this, it seems that they have not observed whether ants actually visit the capsules.

On the other hand, in the case of Portulaca oleracea, when the fruit ripens, it bursts open and actively scatters its seeds, resulting in automatic dispersal. After this, the scattered seeds on the ground are carried away by ants that come looking for the aril.

That's not the only difference. Portulaca oleracea lacks an appendage called omphaladium on its seeds, whereas Portulaca oleracea var. triangularis has it. Why is that? Omphalodium absorbs moisture, regulates the moisture balance of the seed, and promotes germination.

In Portulaca grandiflora, the seeds remain inside the fruit for a considerable period, so it takes time for them to germinate. In such cases, it is necessary to reduce the amount of water and maintain a dry state, allowing germination to occur at the appropriate time. Therefore, it does not contain Omphalodium.

In contrast, the seeds of *Potamogeton crispus* are quickly scattered on the ground and carried away by ants. In semi-arid areas, the seeds need to germinate before the moisture dries up. This is why it seems to possess *Omphalodium*.

Although these two species have quite different fruit life cycles, the reason for this difference remains unclear. However, since *Potamogeton crispus* has a life cycle that depends on ants, whether or not suitable ants for seed dispersal existed in the environment where its ancestors lived likely had a significant impact. The environment in which the seeds can freely roll on the ground in the wind may also be a contributing factor.

There are several theories about the origin of the Japanese name "hazeran," including that it comes from the way the flowers bloom one after another as if bursting (hazeru), that the round red fruit resembles a bursting sparkler, and that it comes from the way the seeds burst and scatter. However, it can be said that this description applies most to the triangular hazeran.

References

Flora of North America Editorial Committee. 2004. Flora of North America (Vol. 4 Magnoliophyta: Caryophyllidae, Part 1). Oxford University Press, 584pp. ISBN: 9780195173895

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Shimizu, K., Morita, H., & Hirota, S. 2001. Illustrated Guide to Naturalized Plants of Japan: 600 Species of Plant Invaders (Revised). National Rural Education Association, Tokyo. 553pp. ISBN: 9784881370858

Shivanna, KR 2019. A Novel Autogamous Self-Pollination Strategy Involving Closing of Perianth Lobes in Talinum fruticosum (L.) Juss. Proceedings of the National Academy of Sciences, India Section B: Biological Sciences 89(4): 1407-1411. https://doi.org/10.1007/s40011-018-01066-6

Uemura, Shuji; Katsuyama, Teruo; Shimizu, Norihiro; Mizuta, Mitsuo; Morita, Hirohiko; Hirota, Shinichi; and Ikehara, Naoki. 2015. Illustrated Guide to Naturalized Plants of Japan: 500 Species of Plant Invaders (Revised and Expanded Edition, Vol. 2). National Rural Education Association, Tokyo. 595pp. ISBN: 9784881371855

Valerio, R. & Ramirez, N. 2003. Exogamic depression and reproductive biology of Talinum paniculatum (Jacq.) Gaertner (Portulacaceae). Acta Botánica Venezuelica 26(2): 111-124. ISSN: 0084-5906, http://ve.scielo.org/scielo.php?script=sci_abstract&pid=S0084-59062003000200001&lng=en&nrm=iso&tlng=en

Veselova, TD, Dzhalilova, KK, Remizowa, MV, & Timonin, AC 2012. Embryology of Talinum paniculatum (Jacq.) Gaertn. and T. triangulare (Jacq.) Willd. (Portulacaceae sl, Caryophyllales). Wulfenia 19: 107-129. ISSN: 1561-882X, http://msu-botany.ru/gallery/veselovaetal-3.pdf

Source

This article is a significantly expanded version of a piece originally published in the following book.

Monotropa uniflora, Monotropa uniflora var. japonica, and Monotropa uniflora are three species of plants that grow in the dark forest floor, where photosynthesis has been lost. They lack normal leaves, which have degenerated into scale leaves. They only have stems and flowers, and their entire bodies are white because they lack chlorophyll. They are known as mycoheterotrophic plants, but distinguishing them can be difficult without experience. However, upon closer inspection, various differences can be observed. Monotropa uniflora and Monotropa uniflora var. japonica belong to the Ericaceae family, while Monotropa uniflora var. japonica belongs to the Orchidaceae family, so their flower structure and ecology are completely different. Monotropa uniflora and Monotropa uniflora var. japonica belong to the same Ericaceae family, but their flowering period, inflorescence, flowers, ovary, and fruit differ. Recently, Monotropa uniflora var. kirishimaensis, which has red flowers, has been discovered, so it is also necessary to distinguish it from these species. These species have stopped photosynthesizing and depend on fungi for nutrients. There are several reasons for this, but the idea that it is the most adaptive for growing in the dark forest floor is easy to understand. The pure white flowers of Monotropa uniflora and Monotropa uniflora appear colored to the eyes of insects, and their downward-facing structure makes them most frequently visited by bumblebees, who contribute significantly to pollination. On the other hand, Monotropa uniflora is self-pollinating. These are also thought to be adaptations to the dark forest floor. The fruit of Monotropa uniflora is a berry, and its seeds are known to be dispersed by cockroaches, but Monotropa uniflora has a capsule, and its seeds are dispersed by wind, which is the opposite. This may be influenced by the fruiting period. This article will explain the classification, evolution, pollination ecology, and seed dispersal of Monotropa uniflora, Monotropa uniflora, and Monotropa uniflora.

Three plant species that grow in the dark forest floor where photosynthesis has been lost

Monotropastrum humile, also known as silver dragon grass or ghost mushroom, is a perennial herb distributed in the southern Kuril Islands, Hokkaido, Honshu, Shikoku, Kyushu, and Ryukyu Islands of Japan; Sakhalin, the Korean Peninsula, China, Taiwan, Myanmar, northern India, and the Himalayas. It inhabits the forest floor of coniferous and broadleaf forests. It mainly grows on moist humus, and its finely branched roots usually form a clump. Its Japanese name, "Ginryusou" (silver dragon grass), is said to come from the resemblance of its appearance, enclosed in vestigial scale-like leaves, to a dragon covered in scales. It belongs to the genus Monotropastrum in the family Ericaceae.

Monotropa uniflora, also known as autumn silver bellflower, is a perennial herb widely distributed in Hokkaido, Honshu, Shikoku, and Kyushu in Japan; as well as in the temperate regions of Southeast Asia and North America. It grows in somewhat shady areas within hilly and mountainous forests. Its Japanese name comes from its resemblance to the silver bellflower (Monotropa uniflora). It belongs to the genus Monotropa in the family Ericaceae.

Epipogium roseum, also known as Tashiro Orchid, is distributed in Honshu (south of Gunma Prefecture), Shikoku, Kyushu, and the Ryukyu Islands in Japan; China, Taiwan, Southeast Asia, India, Australia, New Caledonia, and West Africa. In Japan, it is a perennial herb that grows in evergreen broad-leaved forests. Its Japanese name comes from the name of its discoverer, Zentaro Tashiro, and was given by Dr. Tomitaro Makino. It belongs to the genus Epipogium in the family Orchidaceae.

Neither of them has normal leaves; their leaves have degenerated into scale-like leaves. They only have stems and flowers, and their entire bodies are white because they lack chlorophyll. They are known as mycoheterotrophic plants (i.e., mycoparasitic plants, saprophytic plants). Because their entire bodies are white, it can be difficult to distinguish them without experience. In particular, Monotropa uniflora and Monotropa uniflora look very similar in shape.

What are the differences between Monotropa uniflora, Monotropa uniflora var. japonica, and Monotropa uniflora?

However, upon closer examination, various differences can be observed (Kanagawa Prefecture Flora Survey Association, 2018).

First, while Monotropa uniflora and Monotropa uniflora belong to the Ericaceae family, Tashiro orchid belongs to the Orchidaceae family, so their flower structures and ecology are completely different.

While numerous scale-like leaves can be seen in Monotropa uniflora and Monotropa uniflora var. japonica, in Monotropa japonica var., there are only about 1 to 8 scale-like leaves, spaced apart.

Furthermore, regarding the inflorescence, while Monotropa uniflora and Monotropa uniflora var. japonica have only one to a few flowers that hang downwards, Monotropa japonica produces a raceme inflorescence with 2 to 16 flowers.

Regarding the structure of the flower, in Monotropa uniflora and Monotropa uniflora var. japonica, the calyx and petals overlap to form a tubular bell shape, but in Orchidaceae, there is a unique shape called the "orchid-shaped corolla" common to all plants in the Orchidaceae family, consisting of three sepals and three petals, with two "lateral petals" and a central "labellum" combined.

Although Monotropa uniflora and Monotropa uniflora var. japonica belong to the same Ericaceae family, they differ in their flowering period, inflorescence, flowers, ovary, and fruit.

Regarding the flowering period, Monotropa uniflora flowers in April-May and July, while Monotropa uniflora var. japonica flowers in September-October.

Regarding the inflorescence, in Monotropa uniflora, one to several flowers hang downwards at the tip of the stem, whereas in Monotropa uniflora var. japonica, only one flower is attached to the end of the stem.

Regarding the flowers, in Monotropa uniflora, the sepals and upper parts of the petals are not notched, whereas in Monotropa uniflora var. japonica, there are irregular notches (serrations, teeth) on the upper parts of the sepals and petals.

Regarding the ovary, in Monotropa uniflora, it has one chamber and the ovule is a parametrial placenta, whereas in Monotropa uniflora var. japonica, the ovary has 3 to 5 chambers and is axillary placenta.

Regarding the fruit, Monotropa uniflora has a berry that does not split open when ripe, grows obliquely sideways, and retains its sepals and petals even when fruited, whereas Monotropa uniflora has a capsule that splits open when ripe, grows upwards, and its sepals and petals fall off when fruited.

Regarding the seeds, Monotropa uniflora lacks wings, while Monotropa uniflora var. japonica does.

I've listed quite a few differences, but practically speaking, you can distinguish them simply by checking the flowering period and the way the petals are lobed.

Furthermore, a variety of Monotropastrum , Monotropastrum humile f. roseum, has been identified that has a red ovary inside the flower.

Also in the same family, Ericaceae, subfamily Monotropinae, is * Hypopitys monotropa*, but it can be easily distinguished by the fact that it has 4 to 8 flowers in a raceme at the end of the stem, the plant body is pale yellowish-brown, and the flowers bloom from June to August.

What is the difference between Monotropa uniflora and Monotropa kiusiana?

Furthermore, there is a species called Monotropastrum kirishimense, which has recently been discovered as a new species similar to Monotropastrum verum (Suetsugu et al., 2023). Currently, it has been confirmed in Osaka, Wakayama, Shizuoka, Gifu, Kagoshima, and Miyazaki prefectures. The differences between it and Monotropastrum verum are quoted below.

• While the petals and sepals of *Monotropa uniflora* are reddish, those of *Monotropa uniflora* are transparent to white. Similarly, *Monotropa uniflora* (a color variant of *Monotropa uniflora*) also appears reddish. However, the actual color comes from the ovary inside the flower; the color of the ovary is simply showing through, and the petals and sepals are actually transparent to white.
• The number of sepals in Monotropa uniflora is 4 to 11, which is more than the usual 2 to 3 in Monotropa uniflora. Also, in Monotropa uniflora, the sepals are always in contact with the petals, whereas in Monotropa uniflora they are often separated from the corolla tube.
• The flowers of *Monotropa uniflora* are rounder than those of *Monotropa uniflora* from the early stages of flowering.
• The above-ground portion of *Monotropa uniflora* is often short, less than 5 cm. (*Monotropa uniflora* is often 5 cm or longer.)
• The rhizomes of Monotropa uniflora are often long, exceeding 10 cm. (Monotropa uniflora rhizomes are usually less than 5 cm.)
• The roots of *Monotropa uniflora* are less distinct than those of *Monotropa uniflora*, blending seamlessly with the surrounding soil, and their tips barely protrude, making them almost invisible to the naked eye. (A cluster of white mycelium can be seen.)

『Kobe University Press Release』

What is the adaptive significance of ceasing photosynthesis?

The three species Monotropa uniflora, Monotropa uniflora var. japonica, and Monotropa japonica are known as mycoheterotrophic plants (i.e., mycoparasitic plants, saprophytic plants).

"Heterotrophy" is the opposite of "autotrophy," which synthesizes nutrients on its own through photosynthesis, etc. Heterotrophy is a way of life that relies on obtaining nutrients from other organisms. This applies to many animals, including humans.

In the case of Monotropa uniflora, Monotropa uniflora var. japonica, and Monotropa uniflora, they do not perform photosynthesis but instead steal carbon, which is a nutrient, from fungi (the kind called mushrooms and molds) that grow on trees through their roots.

They were once commonly called "saprophytic plants" because they were thought to be able to obtain nutrients from decaying leaves and soil. While they are still sometimes referred to this way out of convention, it's not a very desirable term.

In the case of Monotropa uniflora, it is known that the majority of mycorrhizal fungi are ectomycorrhizal fungi of trees (Russulaceae, Russula genus), and that a wide range of species within the Russula genus are utilized as mycorrhizal fungi (Yokoyama et al., 2013).

In the case of *Psathyrella tashiroensis*, it has been found to form mycorrhizal symbiosis with fungi of the family Psathyrellaceae (Tanigame, 2011).

Why did mycoheterotrophic plants stop photosynthesis and start obtaining nutrients from fungi?

There are two possible explanations for this (Suetsugu & Kato, 2014).

The most common reason is that parasitizing fungi allows them to survive even in the dark forest floor where there are few competitors. Photosynthesis is a method of nutrient synthesis that does not depend on other organisms, but on the other hand, it can be said that it is a way of life that is highly dependent on light. In the dark forest floor where there is little light, it can be said that a way of life that depends on other organisms is quite advantageous. In fact, Monotropa uniflora, Monotropa uniflora var. japonica, and Monotropa uniflora all live in the shade, so it is quite plausible that they have such advantages.

Another reason is that, when stressed, they can survive by remaining underground instead of extending their plant bodies above ground. While ordinary photosynthetic plants also keep their plant bodies underground, in that case, they still use nutrients through respiration and other metabolic processes while confined underground. By parasitizing fungi, they can obtain carbon and increase their survival rate.

The pure white flowers of the Indian pipe plant are exclusively for bumblebees! What's the reason?

The flowering period for Monotropa uniflora is from spring to summer (April-May and July). The inflorescence has a flower stalk and is 10-20 cm tall. The flowers bloom facing downwards and are tubular-bell shaped. The petals and calyx are oblong and pure white. There are 1-5 sepals and 3-5 petals. Although not visible in the photo, the stigma of the pistil is a purple disc that occupies most of the flower, and 6-10 stamens are arranged alternately in two rows around the pistil.

Although the flowers appear plain white to the human eye, they reflect ultraviolet light, making them conspicuous to insects (Klooster et al., 2009).

What kinds of insects visit this flower?

Studies conducted by various research groups in Japan have consistently shown that the site is visited almost exclusively by bumblebees of the genus Bombus, primarily Bombus diversus diversus (Tanaka, 1978; Ushimaru & Imamura, 2002; Sueji & Kato, 2014).

It is said that Monotropa uniflora flowers can bloom in dense clusters within an area of about 20 cm square. When a bumblebee comes to try to drink the large amount of nectar deep inside, its head and legs attach to the stamens located next to the pistil.

Because the flowers face downwards, only bumblebees that can skillfully hang down can insert their mouths, the depth to the nectar is suitable for the length of a bumblebee's mouth, and the entrance to the nectar is closed, it is a somewhat unusual flower, but it can be said to be a flower form that is well-suited for bumblebees (Tanaka, 1978).

The bumblebees that visit are thought to be queen bees that begin their activity in the spring, but it has been suggested that worker bees may also come (Ushimaru & Imamura, 2002).

Why does the Indian pipe plant rely on bumblebees for pollination?

For Monotropa uniflora, a mycoheterotrophic plant that grows in the dark forest floor, relying on pollination from insects that prefer bright environments, such as small bees and honeybees, is extremely difficult. On the other hand, bumblebees can regulate their body temperature and therefore forage even in dark environments. For this reason, it is thought that the shape of the flower has evolved to be specialized for bumblebees (Suetsugu & Kato, 2014).

There is considerable variation in flower size (Ushimaru & Imamura, 2002). While larger flowers might seem more attractive to insects and thus have a higher chance of pollination, this tendency has not been demonstrated in studies. The reason for the small flowers remains unknown. This flower still holds many mysteries.

It's also quite unusual that the ovary of the red-flowered silver pipe plant turns red.

Are the insects that visit Monotropa uniflora the same as those that visit Monotropa uniflora?

The flowering period of Monotropa uniflora is from September to October. The inflorescence has a flower stalk and is 10 to 30 cm tall. The flowers bloom facing downwards and are tubular-bell-shaped. The petals and calyx are lanceolate to oblong and pure white. There are 3 to 5 sepals and 3 to 8 petals. Although not visible in the photo, the stigma of the pistil is a yellowish-brown disc that occupies most of the flower, and there are usually 10 stamens arranged around the pistil.

In the case of Monotropa uniflora, the flowers also reflect ultraviolet light, making them conspicuous to insects (Klooster et al., 2009).

Although there are differences in flowering period and the number of stamens, the basic structure is the same as that of Monotropa uniflora. Are the insects that visit this flower the same as those that visit Monotropa uniflora?

While no research in Japan could be found, a study conducted in Ohio, Indiana, Kentucky, and Tennessee in the eastern United States revealed that while the Bombus spp., which is found only in Honshu, the Korean Peninsula, and Ussuri, was not present, several species of the genus Bombus were indeed visiting (Klooster & Culley, 2009). Syrphidae were the next most frequent visitors, followed by a small number of Apidae, but their contribution to pollination may be low due to the downward-facing flowers. It seems reasonable to conclude that the genus Bombus is the most important pollinator.

Incidentally, this study also investigated pollinating insects of closely related species not found in Japan, such as *Monotropa uniflora* and *Monotropsis odorata*, and in these species as well, multiple species of the genus *Bumblebee* were found to be the most important pollinators.

However, it was found that there are significant differences in how pollen adheres to bumblebees between the genera Monotropa and Monotropa and the genus Monotropis.

In the genera Monotropa and Monotropa, as mentioned above, pollen adheres to the heads and thoraxes of bumblebees as they search for nectar in the flowers. This occurs because the anthers have slits, and the pollen falls off along these slits, spilling onto the inner wall of the corolla.

On the other hand, in the genus Monotropis, the anthers have two pores, and pollen is not easily released from the anther sac.

So how do bumblebees get pollen? Bumblebees hang from flowers and vibrate their wings rapidly. This causes pollen to fall out through the holes in the anthers. This is called "vibration pollination," and it is a well-known pollination method in the Solanum genus, which includes eggplant. It prevents nectar robbing and ensures that pollen is only passed to bees that can vibrate, such as bumblebees.

But ultimately, do these differences reflect any ecological differences?

Although not mentioned in this paper, it would be reasonable to assume that the genus Monotropis has flowers that are more specifically adapted to bumblebees.

In fact, records of pollinating insects show that while hoverflies and bees visited a small number of flowers in the Monotropa genus and Monotropa uniflora, their numbers were considerably reduced in the Monotropis genus.

While it's generally said that he specialized in bumblebees, perhaps he could be considered relatively generalist within the Pyrolainae subfamily.

There are still other questions remaining. Queen bumblebees, which become active in spring, visit Monotropa uniflora, but what kinds of bumblebees, and within the same species caste, visit Monotropa uniflora? This point also remains unclear.

Did the flowers of the Tashiro orchid only self-pollinate?!

Tashiro orchids bloom from June to July. They produce racemes at the top of the stem, bearing 2 to 16 flowers. The racemes are 10 to 20 cm long and extend above the flowerless bracts. The flowers open from the bottom upwards. The bracts usually have reddish-purple spots. The flowers have a characteristic "orchid-shaped corolla" common to all plants in the orchid family, consisting of three sepals and three petals, with two "lateral petals" and a central "labellum" combined. The sepals are linear-lanceolate, with nearly pointed tips. The lateral petals resemble the sepals but are slightly shorter, wider, narrowly ovate-lanceolate, and acute to obtuse. The labellum, when spread, is broadly ovate, with reddish-purple spots, and its edges are finely serrated. There is a spur at the base of the labellum, which is oblong (cylindrical), with a rounded tip, and protrudes towards the ovary.

Tashiro orchid has a typical flower shape for the orchid family, and it also produces fragrance and nectar, so it certainly seems like it would attract insects.

However, a study conducted in Xishuangbanna Dai Autonomous Prefecture, China, found that the only insect that visits this flower is the Asian honeybee , Apis cerana cerana, which is widely distributed in Asia (Zhou et al., 2012).

Moreover, the pollen did not adhere to the bodies of the Eastern honeybees, and therefore did not contribute at all to their fruit production! In other words, although insects visited the Tashiro orchid, it was entirely self-pollinating, producing fruit and seeds. Self-pollination occurred at the bud stage, one day before flowering.

Why are they doing this?

This, too, is likely influenced by its habitat. *Tashiro orchid* grows in very shady forest floors, where insect pollination is virtually impossible. It's possible even bumblebees struggled with pollination.

Therefore, the Tashiro orchid has become self-pollinating, seemingly reaching the ultimate method that surpasses even the Monotropa uniflora and Monotropa uniflora look-alike.

The fragrance and honey are thought to be remnants of their ancestors.

The fruit of the Indian pipe is a berry, and its seeds were dispersed by that disliked creature?

After flowering, Monotropa uniflora produces dull white, fleshy fruits (berries). While this might sound delicious, they are apparently not sweet to humans. The seeds are embedded within the fruit's pulp. Recent research has explored how these seeds are dispersed and how Monotropa uniflora expands its distribution (Uehara & Sugiura, 2017).

We used infrared motion sensors to investigate which insects visit fruit in the wild. As a result, we found that six groups of insects visited: harvestmen, springtails, camel crickets, cockroaches, darkling beetles, and ants. However, only the Japanese cockroach (German cockroach) ingested the seeds. The other species either nibbled on the fruit pulp or visited only in very small numbers. It is natural to conclude that the Japanese cockroach is almost exclusively responsible for dispersing the seeds over long distances.

In this study, to further investigate whether the German cockroach (Erythrina japonica) actually carries the seeds alive, a TTC staining test was conducted to determine if the plants were still alive. This allowed researchers to determine how many seeds survived after being expelled from the cockroach's body.

As a result, approximately half of the seeds survived. Moreover, this result was no different from the survival rate of seeds directly extracted from the fruit by hand, suggesting that they were hardly affected by cockroach digestion.

The activity period of the Japanese cockroach coincides with the fruit-producing period, and since it lives on the ground, it is highly likely to come into contact with the mycelium of the Russulaceae fungi that it parasitizes. Its high flight ability also suggests that it can carry seeds over long distances. It seems to be a very convenient seed carrier for Monotropa uniflora.

However, the Japanese cockroach (Tomioka et al., 2016) is said to have a distribution that extends from the vicinity of Tokyo as far north as various parts of the Pacific Ocean southward, and along the Sea of Japan coast as far south as Ishikawa Prefecture, with its southern limit reaching Tanegashima Island. Although it has now spread as far north as Tochigi Prefecture, it does not exist further north than that. Therefore, it is highly likely that the populations in the Southern Kuril Islands and from northern Japan to Hokkaido are dispersed by other animals.

Based on these circumstances, research was also conducted in Hokkaido, where it was discovered that seed dispersal also occurs through camel crickets, woodlice, and earwigs (Suetsugu et al., 2024).

It seems that Monotropa uniflora is a plant that lives in harmony with many creatures, including fungi, bumblebees, and German cockroaches. When studying this species, it seems necessary to observe it while being aware of its relationships with various living things.

Why are the fruits of Monotropa uniflora capsules?

On the other hand, the fruit of Monotropa uniflora is an erect, oval-spherical capsule, 1-1.5 cm long, which is completely different from the flowers of Monotropa uniflora, which were similar in appearance.

How does Monotropa uniflora disperse its seeds?

A Japanese study that closely observed the morphology of the seeds found that the seed coat extends beyond surrounding the inner milky pulp, forming a wing-like structure, which is thought to allow the seeds to be dispersed by wind (Ugajin & Endo, 2018).

Some people who learn about this might think that capsules are a more primitive characteristic within the Pyrola subfamily. This is because there are many other wind-dispersed plants, and there are no examples of plants relying on cockroaches to eat their fruit. It seems that the evolution occurred from wind-dispersed capsules to cockroach-dispersed berries.

However, similar studies have revealed that the evolution from berries to capsules actually occurred. This can be determined by statistically analyzing the various characteristics of seeds of each species. It was also found that this evolution occurred four times independently.

Why did the evolution from cockroach-dispersed berries to wind-dispersed capsules occur?

Unfortunately, the reason for this is still not well understood. However, in my opinion, there are some possible reasons for this in the case of Japanese Monotropa uniflora and Monotropa uniflora var. japonica.

The fruiting period for Monotropa uniflora is from May to September. Therefore, as mentioned above, this overlaps with the activity period of adult German cockroaches, and it is possible that they will eat the fruit.

On the other hand, since Monotropa uniflora has a later flowering period, its fruiting period is from October to November. By this time, the adult Japanese cockroaches have finished giving birth and are gone. Japanese cockroaches are known to overwinter mainly as sixth-instar larvae (Tomioka et al., 2016). They may need to be of a certain size to eat the fruit and disperse their seeds.

Therefore, the delayed fruiting period may have resulted in wind dispersal. However, this is just a hypothesis, and a comprehensive study of various closely related species would be necessary to determine the actual cause.

References

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Klooster, MR, Clark, DL, & Culley, TM 2009. Cryptic bracts facilitate herbivore avoidance in the mycoheterotrophic plant Monotropsis odorata (Ericaceae). American Journal of Botany 96(12): 2197-2205. https://doi.org/10.3732/ajb.0900124

Klooster, MR, & Culley, TM 2009. Comparative analysis of the reproductive ecology of Monotropa and Monotropsis: two mycoheterotrophic genera in the Monotropoideae (Ericaceae). American Journal of Botany 96(7): 1337-1347. https://doi.org/10.3732/ajb.0800319

Suetsugu, K., Hirota, SK, Hsu, TC, Kurogi, S., Imamura, A., & Suyama, Y. 2023. Monotropastrum kirishimense (Ericaceae), a new mycoheterotrophic plant from Japan based on multifaceted evidence. Journal of Plant Research 136(1): 3-18. https://doi.org/10.1007/s10265-022-01422-8

Sueji, Kenji & Kato, Makoto. 2014. Various adaptive evolutions that enabled a mycoheterotrophic lifestyle—particularly changes in pollination methods. Frontiers in Plant Science 5: 93-109. ISSN: 2432-9819, https://doi.org/10.24480/bsj-review.5c3.00056

Suetsugu, K., Kimura-Yokoyama, O., & Kitamura, S. 2024. Earwigs and woodlice as some of the world's smallest internal seed dispersal agents: Insights from the ecology of Monotropastrum humile (Ericaceae). Plants, People, Planet 6(6): 1159-1166. https://doi.org/10.1002/ppp3.10519

Tanaka, Hajime. 1978. Pollination of Monotropa uniflora. Journal of Japanese Plant Research 53(7): 201-202. ISSN: 0022-2062, https://doi.org/10.51033/jjapbot.53_7_6889

Tanigame, Takahiro. 2011. Studies on elucidating the mycorrhizal symbiotic system of orchid plants. Bulletin of the Mycological Society of Japan 52(1): 11-18. https://doi.org/10.18962/jjom.jjom.H22-02

Tomioka, Y., Satake, H., & Tanikawa, R. 2016. Distribution of Blatella niponica Asahina from northern Kanto to southern Tohoku and its northernmost record. Sanitary Zoology 67(3): 177-181. https://doi.org/10.7601/mez.67.177

Uehara, Y., & Sugiura, N. 2017. Cockroach-mediated seed dispersal in Monotropastrum humile (Ericaceae): a new mutualistic mechanism. Botanical Journal of the Linnean Society 185(1): 113-118. https://doi.org/10.1093/botlinnean/box043

Ugajin, C., & Endo, Y. 2018. Comparative anatomy of the seeds of Monotropastrum humile and Monotropa uniflora (Monotropoideae, Ericaceae). Journal of Japanese Botany 93(3): 147-154. https://doi.org/10.51033/jjapbot.93_3_10857

Ushimaru, A., & Imamura, A. 2002. Large variation in flower size of the myco-heterotrophic plant, Monotropastrum globosum: effect of floral display on female reproductive success. Plant Species Biology 17(2-3): 147-153. ISSN: 0913-557X, https://doi.org/10.1046/j.1442-1984.2002.00077.x

Yokoyama, J., Takahashi, M., & Yoshida, M. 2013. Mycorrhizal fungi of Monotropa uniflora growing in a cedar forest in Iwaki City, Fukushima Prefecture. Bulletin of the Urabandai Lake Research Station, Faculty of Science, Yamagata University 20: 4-8. http://id.nii.ac.jp/1348/00003262/

Zhou, X., Lin, H., Fan, XL, & Gao, JY 2012. Autonomous self-pollination and insect visitation in a saprophytic orchid, Epipogium roseum (D. Don) Lindl. Australian Journal of Botany 60(2): 154-159. https://doi.org/10.1071/BT11265

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This article is a significantly expanded version of the one included in the following book.

Polygonatum odoratum, Polygonatum sibiricum, Polygonatum humile, and Disporum sessile are all species that bloom in spring and are commonly found in gardens and as wildflowers, but they can be a little difficult to distinguish as they are often sold mixed together. Therefore, we have summarized the botanical distinguishing features of the Polygonatum genus. They can be distinguished mainly by the way the flowers grow, as well as by the leaves and stems. All of these species have downward-facing flowers, but do you know what role they play in the wild? Polygonatum odoratum is the most well understood, as it is an important source of nutrition for the queen bumblebee, which becomes active in spring. Also, Polygonatum odoratum tends to produce male flowers with only stamens at the top of a single stem and hermaphroditic flowers with both stamens and pistils at the bottom. There are various theories as to why this is the case, but one theory is that it is the result of Polygonatum odoratum cleverly distributing energy due to nutrient deficiencies. The fruit is a berry and is probably dispersed by birds. This article will explain the classification, pollination ecology, and seed dispersal of Polygonatum species.

What are Polygonatum odoratum, Polygonatum sibiricum, Polygonatum humile, and Polygonatum odoratum?

Polygonatum odoratum, also known as Amadokoro in the broad sense, is a perennial herb distributed from Hokkaido to Kyushu in Japan, as well as in Korea, China, Taiwan, Mongolia, Russia, and Europe, inhabiting sunny grasslands and forest edges (Kitamura et al., 1957). Of these, the Japanese variety var. pluriflorum is found in Japan and Korea. Its young leaves and rhizomes are sweet and used for food and medicine (Tanaka, 1995).

Polygonatum odoratum var. thunbergii, also known as mountain sweet jasmine, closely resembles Polygonatum odoratum, but its underside has fine, hair-like projections.

Polygonatum falcatum, also known as Solomon's seal, is a perennial herb distributed in Hokkaido, Honshu, Shikoku, Kyushu, and Korea, mainly growing in bright deciduous forests.

Polygonatum lasianthum, also known as Miyama Narukoyuri, is distributed in Hokkaido, Honshu, Shikoku, Kyushu, and Korea, and mainly grows in bright deciduous forests.

Polygonatum macranthum, also known as the large-flowered lily, is a perennial herb distributed in Hokkaido, Honshu, Shikoku, and Kyushu, growing in grasslands, deciduous forests, and forest edges.

Both belong to the genus Polygonatum in the Asparagaceae family (formerly Asparagaceae), and are commonly found both in gardens and as wildflowers. Their leaves and flowers are similar, and their flowering periods are close together, so you may have trouble distinguishing them.

[Seed Plant Encyclopedia #087] What are the species of the Asparagaceae family? Photo list

The Asparagaceae family, also known as the Asparagaceae family, consists of perennial herbs, woody plants, or vines. They have rhizomes or bulbs. Leaves are alternate, opposite, or whorled, and may be clustered at the base of the stem. The terminal branches may also be leaf-like (Asparagus genus, Ruscus aculeatus...).

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What are the differences between Polygonatum odoratum, Polygonatum sibiricum, Polygonatum falcatum, and Polygonatum odoratum?

Although they look very similar at first glance, they can be distinguished as follows (Kanagawa Prefecture Flora Survey Association, 2018).

First, *Polygonatum odoratum* is completely different from other species in that its inflorescence stalk (the slender part on which the flower attaches to the plant) is long, spreads outwards, and bears 1 to 3 flowers. Also, its filaments are densely covered with long hairs. In other species, the inflorescence stalk hangs downwards, and the filaments are hairless or only have minute projections.

Of the remaining species, Polygonatum odoratum and Polygonatum sieboldii have ridged stems except at the base. On the other hand, Polygonatum odoratum and Polygonatum sieboldii have cylindrical stems without ridges, which is a major distinguishing feature.

The difference between Polygonatum odoratum and Polygonatum sieboldii is that Polygonatum odoratum has a smooth underside to its leaves, while Polygonatum sieboldii has tiny protrusions on the underside of its leaves.

The difference between Polygonatum odoratum and Polygonatum sibiricum is that in Polygonatum odoratum, the underside of the leaves is covered with a powdery white substance and is smooth, and the filaments are swollen at the base and have minute projections except for the tip, whereas in Polygonatum sibiricum, there are minute projections on the veins on the underside of the leaves and the filaments are smooth.

Although Disporum sessile may look similar at first glance, it is a completely different member of the Colchicaceae family. Its leaves have three distinct veins that are clearly more deeply indented than those of the Polygonatum genus, its inflorescences are attached to the stem apex, and it usually lacks a peduncle.

[Seed Plant Encyclopedia #069] What are the species of Colchicaceae? Photo List

Colchicaceae are perennial herbs. They have corms or rhizomes. Leaves are alternate, opposite, or whorled, sometimes clustered at the base of the stem. Flowers are solitary or borne in racemes or cymes, exhibiting considerable diversity. They usually bear bisexual flowers. Perianth segments are separate or fused, with 6...

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Other species such as *Campanula punctata* and *Polygonum thunbergii* are also present, but they will be omitted here. For more details, please refer to the Kanagawa Prefectural Flora Survey Association (2018).

What is the structure of a flower?

Polygonatum odoratum blooms from April to May, producing slender, bell-shaped (or oval-shaped) white flowers on single or bifurcated pedicels that emerge from the base of the leaves. The flowers droop as they open, and their tips are tinged with green. The flowers on the stem bloom from the bottom upwards.

Polygonatum odoratum blooms from May to June, with flower stalks that curve downwards from the base, bearing 3 to 8 white flowers. The flowers also droop as they open, and the tips are tinged with green, but their shape is slightly thinner than that of Polygonatum odoratum.

Polygonatum odoratum flowers from May to June. Its stalks are obliquely ascending, with a short base fused to the stem, and gently curved in an arc due to the weight of the flower. The flowers are 17-21 mm long, with a short stalk of about 0.5 mm at the base. The tip is shallowly 6-lobed, the lobes do not curve back, and there are small projections at the tips. The inner surface is covered with short hairs. There are 6 stamens, the filaments are covered with long, soft hairs and fused to the corolla up to the middle. The pistil's style is hairless, and the tip is not divided.

The flower was specifically designed for pollination by bumblebees!?

What kinds of insects visit these downward-facing flowers? Of these species, the ecology of the flowers of Polygonatum odoratum has been studied in detail (Tanaka and Hirano, 2000; Hirose et al., 2002; Kono et al., 2004).

Bumblebees visit this flower. This is a typical example of how downward-facing flowers are chosen by bees that can firmly cling to them (Tanaka and Hirano, 2000).

Moreover, the bumblebees that visit are often queen bees, and it is believed that this is a major food source for the bumblebee queens before they begin their activity and build their nests.

Why does Polygonatum odoratum produce both male and hermaphroditic flowers on a single stem?

Incidentally, in Polygonatum odoratum, the upper part of a single stem tends to produce male flowers with only stamens, while the lower part produces hermaphroditic flowers with both stamens and pistils. Not only that, but the size of the flowers themselves also decreases as you go higher up the stem. This change is continuous, and the fruiting rate in nature also decreases as you go higher.

Why are they doing that? It seems like they could produce more fruit if they made all of them into large, hermaphroditic flowers.

There are two main hypotheses for this (Guitián & Medrano, 2001). The first is that bumblebees visit the lower flowers first, so their own pollen gets mixed in, reducing the proportion of pollen from other individuals. Polygonatum odoratum has a characteristic called "self-incompatibility," meaning it cannot produce fruit with its own pollen. As the plant gets higher up, the probability of fruit formation decreases, so the higher up the plant simply doesn't produce pistils at all.

The second reason is that, given the limited amount of nutrients that can be absorbed, nutrients are supplied from the bottom up, leaving insufficient nutrients at the top, so only stamens are produced. If pistils were produced, the fruit would then develop, and a lot of nutrients would need to be transferred to the seeds so that they can survive on their own. However, if only stamens are produced, then pollen production is all that is required. It is thought that either or both of these reasons are the cause.

However, if that's the case, then why not just not produce flowers in the first place? This raises another question, but possible reasons for not doing so include: (1) producing more flowers makes the entire inflorescence more conspicuous and attracts bumblebees; (2) producing extra flowers so that it's okay if the flowers are pollinated but don't produce fruit properly, even if it results in a "miscarriage"; (3) producing extra flowers in advance so that a large amount of fruit can be produced in years when a lot of nutrients are stored; and (4) sometimes wanting to increase the amount of pollen itself (to increase the function of the male) for some reason.

Are there differences in pollination methods among the various varieties of Polygonatum odoratum around the world?

Although they belong to the same species, Polygonatum odoratum var. odoratum, which is widely distributed from Europe to Asia (Guitián & Medrano, 2001), and Polygonatum odoratum var. maximowiczii, which is distributed in northern Eurasia including Hokkaido and northern Honshu in Japan, have also been studied in detail (Harada et al., 2007), and it is thought that similar phenomena are occurring.

The types of bumblebees that visit Polygonatum odoratum differ from those that visit Polygonatum odoratum (Hirose et al., 2002; Harada et al., 2007), and this may be related to the fact that the flowers are larger than those of Polygonatum odoratum.

Are the fruits berries and dispersed by birds?

The fruit, common to all species in the Polygonatum genus, is a berry. A berry is a fruit in which at least part of the pericarp is fleshy or juicy.

The berries of Polygonatum odoratum are spherical, 1 cm in diameter, and black in color. The seeds are ovate, 3.5 mm long.

The berries of Polygonatum odoratum are spherical, 7-10 mm in diameter, and bluish-black in color. The seeds are ovoid, 3 mm long.

The berries of Polygonatum odoratum are spherical, bluish-black, and 8-12 mm in diameter.

The fruit contains many small seeds. Herbaceous berries with such small seeds may rely on being eaten by omnivorous carnivores such as raccoons, bears, and martens for seed dispersal, and there are records of raccoons actually using them (Takatsuki, 2018).

However, given its coloration, it is unlikely that seed dispersal relies solely on mammals with underdeveloped color vision, suggesting that birds are the primary source of seed dispersal (Ueda & Noma, 1999). Studies in the United States have confirmed that Polygonatum species are eaten by birds (Johnson et al., 1985). In the future, understanding which birds consume Polygonatum species in Japan will help determine its distribution.

References

Guitián, J., Guitián, P., & Medrano, M. 2001. Causes of fruit set variation in Polygonatum odoratum (Liliaceae). Plant Biology 3(6): 637-641. ISSN: 1435-8603, https://doi.org/10.1055/s-2001-19369

Harada, J., Sato, M., & Konno, Y. 2007. Fruiting rate of the forest perennial herb Polygonatum odoratum in residual agricultural forests and their surrounding areas. Bulletin of Obihiro University of Agriculture and Veterinary Medicine 28: 41-46. ISSN: 1348-5261, http://id.nii.ac.jp/1588/00001812/

Hirose, Tomoyuki; Hiei, Kayako; and Ohara, Masaru. 2002. Quantitative evaluation of population isolation on the genetic composition of herbaceous plant populations growing in the headwaters of the Tama River: Reproductive ecology of Polygonatum odoratum. Tokyu Environmental Purification Foundation Research Grant, Academic Research 30(215): 8-37. https://foundation.tokyu.co.jp/history/academic/project/215/

Johnson, RA, Willson, MF, Thompson, JN, & Bertin, RI 1985. Nutritional values of wild fruits and consumption by migrant frugivorous birds. Ecology 66(3): 819-827. https://doi.org/10.2307/1940543

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Kitamura, Shiro, Murata, Gen, and Hori, Masaru. 1957. Illustrated Flora of Japan in Color: Herbaceous Plants, Vol. 1, Revised Edition. Hoikusha, Osaka. 297pp. ISBN: 9784586300150

Kohno, S., Ohara, M., Tamura, M., & Hirose, T. 2004. Polygonatum odoratum. pp. 57-64. In: Kohno, S. (ed.). Illustrated Guide to Plant Life History II: Spring Plants, No. 2. Hokkaido University Press, Sapporo. 109pp. ISBN: 9784832913813

Takatsuki, Shigeki. 2018. Characteristics of fruits used by raccoons—a review. Mammalian Science 58(2): 237-246. https://doi.org/10.11238/mammalianscience.58.237

Tanaka, Hajime & Hirano, Takahisa. 2000. The Face of Flowers: Wisdom for Bearing Fruit. Yama-kei Publishers, Tokyo. 191pp. ISBN: 9784635063043

Tanaka, Koji. 1995. Herbal Health Methods: Effectiveness and Usage at a Glance. Kodansha, Tokyo. 123pp. ISBN: 9784061953727

Ueda, Keisuke & Noma, Naohiko. 1999. What carries "grass seeds" in the forest? In: Ueda, Keisuke (Ed.), Seed Dispersal: The Evolution of Mutual Aid Vol. 1 Seeds Carried by Birds (pp. 76-85). Tsukiji Shokan. ISBN: 9784806711926

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This article is a significantly expanded and revised version of content previously included in the following book.

Phalaenopsis orchids are very popular in Japan as high-end potted plants and cut flowers. They are the number one orchid species in terms of both production volume and production value. However, they are also called "Phalaenopsis," which can be confusing. Biologically, however, the terms refer to different areas. Phalaenopsis orchids refer to only one species, " Phalaenopsis aphrodite subsp. formosana," which is distributed only in southern Taiwan and the Philippines, while Phalaenopsis is a general term for about 70 species, including this one, distributed from southern China to Southeast Asia. What is commonly seen in Japan is Phalaenopsis orchids (in the narrow sense). This is related to the large-scale production of Phalaenopsis orchids in Taiwan targeting the Japanese market. Furthermore, another important point is that Phalaenopsis orchids are easier to control the flowering of than other orchids. Phalaenopsis seeds are not commonly sold, which is due to the unique ecological characteristics of the seeds, which depend on symbiotic mycorrhizal fungi for nutrients. While phalaenopsis orchids are often admired for their ornamental properties, their ecology is also fascinating. Inside the flower, there is a rubbery organ called a "sticky body," to which pollen masses are attached. It is believed that when insects approach, the sticky body and pollen masses stick to their backs. However, the type of insect that visits these flowers remains unknown, and despite their common presence, their natural ecology is shrouded in mystery. The fruit is a capsule and is dispersed by wind. This article will explain the classification, history, pollination ecology, and seed dispersal of phalaenopsis orchids.

What is the difference between Phalaenopsis and Mothra orchids?

Phalaenopsis aphrodite (in the broad sense) is distributed in southern Taiwan and the Philippines, and is an epiphytic plant that grows on trees in lowland forests and woodlands with a hot, humid, and well-ventilated environment (Wu et al., 2009).

The Japanese name is written as "胡蝶蘭" in kanji, and it derives from the fact that the flower resembles a butterfly (胡蝶, an old name for a butterfly). This is the same in China, where it is also called "蝶蘭".

It belongs to the genus Phalaenopsis in the family Orchidaceae. Orchidaceae includes "epiphytic orchids" that attach themselves to trees and rocks using their thick roots, and "terrestrial orchids" that root in the ground, and Phalaenopsis belongs to the genus Phalaenopsis, which is an epiphytic orchid (Enoki, 2014).

[Seed Plant Encyclopedia #074] What are the types of orchids? Photo list

Orchids (Orchidaceae) are terrestrial, epiphytic, lithophytic, mycoheterotrophic perennial herbs. Stems are monopodial (single-stemmed) or sympodial (compound-stemmed) with long stems, or they have rhizomes or enlarged pseudobulbs. Leaves are mostly flattened, with a tubular sheath at the base, sometimes reduced to scales. Flowers are…

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Phalaenopsis orchids are very popular in Japan as high-end potted plants and cut flowers.

By the way, if you do a little research, you'll sometimes find that the orchid *Phalaenopsis* is also called *Phalaenopsis*. Is there any biological difference between these two?

Biologically, there are clear differences between these two.

When we refer to it as a " Phalaenopsis aphrodite," we are specifically referring to one species, scientifically known as " Phalaenopsis aphrodite subsp. formosana." This is the most common type in Japan, and almost all of the orchids given as gifts for store openings are of this species.

On the other hand, Phalaenopsis is a general term for species belonging to the genus Phalaenopsis. Depending on the classification, this genus is distributed from southern China to Southeast Asia and is a large group containing about 70 species. In addition, it also includes individuals that have been hybridized through selective breeding of multiple species.

While orchid species other than Phalaenopsis are not typically used for anything, they are traded among orchid enthusiasts. Orchidaceae plants, including the Phalaenopsis genus, are subject to regulations under the Washington Convention (listed in Appendix II), and international trade is generally restricted (Fukunaga & Shimazaki, 2003). However, if local dealers cultivate and propagate them and can prove that they can be propagated stably, they may be traded, but they are often expensive.

What are the differences between Phalaenopsis orchids, Manila Phalaenopsis orchids, and Sunda Phalaenopsis orchids?

Phalaenopsis orchids (in the broad sense) are divided into Phalaenopsis aphrodite subsp. formosana (also known as Taiwanese Phalaenopsis) and Phalaenopsis aphrodite subsp. aphrodite (Manila Phalaenopsis).

Also, since there are many different species in the Phalaenopsis genus, it is impossible to list all the ways to distinguish between them here, but one species with white flowers that is very similar is Phalaenopsis amabilis.

What are the differences between them?

First, the difference between Phalaenopsis orchids (in the broad sense) and Phalaenopsis sundae lies in the "callus," which is the base (root) of the labellum within the petals, or the projection protruding from the base (Morimoto et al., 2016). In these two species, this corresponds to the part with yellow spots.

In Phalaenopsis orchids (in the broad sense), the callus has three bumps on each side, whereas in Phalaenopsis sundae, there are only two.

Furthermore, regarding distribution, while the Phalaenopsis orchid (in the broad sense) is limited to southern Taiwan and the Philippines, the Sunda Phalaenopsis can be found in a relatively wide area including the Philippines, Indonesia, Malaysia, Papua New Guinea, and Australia.

The difference between Phalaenopsis orchids (in the narrow sense) and Phalaenopsis manilai is that Phalaenopsis orchids (in the narrow sense) are distributed in southern Taiwan, have green undersides to their leaves with no redness, possess highly branched panicles, and have relatively small flowers, while Phalaenopsis manilai are distributed in the Philippines, have undersides to their leaves that are usually stained red, possess racemes or slightly branched panicles, and have larger flowers (Wu et al., 2009).

However, the type of orchid commonly seen in Japan is the Phalaenopsis orchid (in the narrow sense). This is related to the large-scale production of Phalaenopsis orchids in Taiwan, which targeted the Japanese market.

When did phalaenopsis orchids become popular? What is their history?

Phalaenopsis orchids have formed a large market as high-end potted plants and cut flowers for corsages and bouquets due to their beauty, large size, and the abundance of large, long-lasting flowers they produce (Enoki, 2014).

In Japan's flower production figures as of 2014, chrysanthemums ranked first with a value of 62.7 billion yen, followed by orchids in second place with a value of 31 billion yen, indicating high demand among flowers.

Furthermore, as of 2013, Phalaenopsis orchids ranked first in production volume and value among commercially produced orchids in Japan, surpassing Cymbidium, Cattleya, and others. They also have a high average price among orchids, making them a plant with extremely high commercial value among horticultural flowers.

Why did phalaenopsis orchids become so popular?

Of course, as mentioned above, the fact that it blooms large and produces many flowers, even among orchid species, was a major factor in its popularity.

However, there are several types of orchids. What makes the Phalaenopsis orchid stand out among them is likely due to its suitability for artificial cultivation and the historical factors that led to the establishment of a commercially viable production system in Taiwan to meet the demand during Japan's bubble economy.

In Taiwan, the original species of Phalaenopsis orchid was discovered relatively late, in the first half of the 20th century (Arai, 2011).

Until the 1970s, orchid cultivation was limited to hobbyists who worked other jobs, producing and breeding on a small scale and selling to wealthy enthusiasts within Taiwan. There were a few exceptional cases of exporting cut flowers and seedlings at the request of Japanese enthusiasts, flower producers, and retailers.

Around the 1980s, in line with the overall growth of Taiwan's floriculture industry, the production of phalaenopsis orchids also began to exceed the level of a hobby, driven by the growing demand within Taiwan.

However, the turning point came in the late 1980s, when large Taiwanese companies entered the orchid production business, primarily for export to the Japanese market, and commercial orchid production was established.

The fact that this industry flourished during this period is largely attributed to Japan's economic boom, known as the "bubble economy." Originally, Cymbidium and Dendrobium orchids were established as high-end gifts for year-end presents, but Phalaenopsis orchids gradually gained popularity, breaking into the market alongside these.

One advantage of the Phalaenopsis orchid over other orchids was the ease with which its flowering could be controlled (Nishimura, 2004). University research revealed that the plants would not flower under high-temperature conditions, but flowering was promoted by exposure to low-temperature conditions. This technique was established in the 1980s, and as a result, Phalaenopsis orchids can now be seen in flower shops all year round.

In the 1990s, the Japanese market gradually became saturated and the bubble economy came to an end. However, as prices fell, exports to the United States and China, and from the mid-2000s to Europe, increased, and ultimately, the product became highly valued in a wide range of regions.

It is estimated that 70-80% of the phalaenopsis orchids currently distributed in Japan come from Taiwan (Phalaenopsis Station, 2025).

In present-day Japan, it is used not only for store opening celebrations, but also for housewarming gifts, 60th birthday celebrations, and offerings at Buddhist memorial services, among other occasions.

Why don't we see seeds in Phalaenopsis orchids?

By the way, when phalaenopsis orchids are sold, it's usually just the flowers. Why don't I ever see phalaenopsis orchid seeds? Given how popular this plant is, it seems strange that seeds aren't readily available.

However, there are reasons why that is difficult.

As will be discussed later, many orchid plants depend on symbiotic mycorrhizal fungi (orchid mycorrhizal fungi), which are classified as basidiomycetes, for their early developmental growth, from seed germination to reaching autotrophic growth through photosynthesis.

Consequently, the seeds of orchids, including Phalaenopsis orchids, are endospermic seeds lacking the endosperm, which is the nutrient storage tissue. Furthermore, the embryos are small and underdeveloped, making spontaneous germination and growth impossible.

In other words, they receive nutrients for germination from symbiotic mycorrhizal fungi, and it's impossible for them to germinate on their own simply by planting them.

Therefore, special artificial manipulation is required to germinate the seeds.

Specifically, seeds are placed in a flask containing an agar medium with nutrients to encourage germination (Arai et al., 2011).

In addition, in some cases, seedlings induced from growth point tissues such as axillary buds, stem apex, and leaf lobes of flower stalks, as well as redifferentiated tissues such as protocorm-like bodies (PLBs), are cultured and propagated in flasks.

Furthermore, the flask seedlings take two years to grow, another two years to flower, and then a total of four years before they can be shipped.

Therefore, it's understandable that the phalaenopsis orchids that ordinary people see are only the flowers.

Did Phalaenopsis orchids perform CAM photosynthesis?

The genus Phalaenopsis is known as a group that performs photosynthesis using the sedum-type organic acid metabolism (CAM) (Yoshimura, 2021).

CAM photosynthesis is a type of photosynthesis that involves a special chemical reaction. Generally, it absorbs carbon dioxide (_CO2) at night and stores it in the plant, which helps to reduce transpiration during the day. This is considered a physiological adaptation that allows terrestrial succulents to secure water in high-temperature, semi-arid environments where they are exposed to harsh moisture conditions. It is advantageous for plants to grow in places where it is difficult to absorb water directly from the soil or in soils with high salinity.

In addition, traits such as fleshy tissue, a thick cuticle, and low stomatal density are often present to enhance water storage capacity.

It is likely that, in addition to inhabiting high-temperature environments, the Phalaenopsis genus, being epiphytic orchids, thrives in environments with low moisture levels, which may have led to the development of succulent leaves and CAM-type photosynthesis.

Did flowers have a mechanism to attach pollen masses to the backs of insects?

In Japan, phalaenopsis orchids are used for ornamental purposes and then wither and die without being pollinated. However, in nature, they must play an important role in attracting insects. How do they attract insects and have their pollen sent to other plants?

The natural flowering period for Phalaenopsis orchids is from April to June. However, with advances in greenhouse cultivation technology, they can be grown to bloom year-round. The flower stalk (the stem that bears the flowers) extends in an arch shape from the leaf axil and bears dozens of flowers (Tsukamoto, 1994). The flowers have a distinctive bilateral symmetrical structure called an "orchid-shaped corolla," which is common to all orchids. Originally, there were three petals and three sepals, but they are cleverly combined to form this structure (Pramanik et al., 2020).

The three sepals—one at the top and two at the bottom—are the same color as the petals, supporting the flower's structure while, along with the petals, attracting insects from afar. The semicircular structures on either side are made up of two petals and are called "lateral petals." In Phalaenopsis orchids, the lateral petals are usually white and, along with the sepals, attract insects from a distance.

The complex-looking structure in the center is a modified petal called the "labellum," which uses its yellow, beard-like protrusions, callus, and scent to lure insects attracted by the petals and sepals deep into the flower.

Above the labellum is a structure called the "column," which is a fused stamen and pistil, and a rubbery, elastic "sticky body." When an insect tries to enter the flower, the sticky body sticks to its back, and as the insect moves, the pollen masses produced by the connected stamens are pulled out and adhere to its back.

This pollen mass is transferred to the pistil of another flower, and pollination takes place. Once the pollen falls off, the flower withers and dies.

It's a famous flower, yet its ecology was unknown?!

As described above, we have a detailed understanding of the flower's structure and pollination mechanism. However, to the best of my knowledge, there are no records of insects directly visiting these flowers in the wild. This may be surprising.

Unfortunately, it's quite common for plants that are familiar in gardens to have poorly understood ecology in the wild. However, overseas researchers familiar with this group speculate that bumblebees and other wasps of similar size may migrate from closely related species (Pridgeon et al., 2014).

It is thought that members of the Phalaenopsis genus, which includes Phalaenopsis orchids, restrict pollinating insects based on flower size (Pramanik et al., 2020), and it is natural to assume that this is the reason why insect pollination is said to be difficult in Japan.

Furthermore, there are differences in color, beard-like protrusions, calluses, and scent depending on the species, which likely reflects differences among pollinating insects.

Whether for ornamental purposes or conservation, it is impossible to properly handle Phalaenopsis orchids without understanding their ecology in the natural world and their symbiotic relationships with other organisms. Further research from this perspective is awaited.

The fruit is a capsule, and the seeds are dispersed by wind.

The fruit of the Phalaenopsis orchid is a capsule that is quite elongated.

Like many orchid species, the seeds are dispersed by wind, with the capsules densely packed with tiny seeds (Miura et al., 2019). It is believed that a single capsule contains tens of thousands to hundreds of thousands of seeds, and as the fruit ripens, gaps form, allowing countless tiny seeds to spill out and be dispersed by a weak breeze.

Protocorms and orchid mycorrhizal fungi are essential for seeds!

As mentioned above, there are some unique characteristics to the seeds of the Phalaenopsis orchid.

Do you know what nutrients plant seeds use to grow?

For example, grasses store energy sources in their endosperm, and legumes store them in their cotyledons. You may have learned this in childhood. However, orchids have no endosperm, and most species lack cotyledons as well (Yeung, 2017)!

The seeds of orchids, including Phalaenopsis orchids, first swell into a spherical shape after germination. This is called a "protocorm." In this stage, they live in symbiosis with fungi called "orchid mycorrhizal fungi," which inhabit the plant's roots.

The orchid mycorrhizal fungi utilize the cellulose of orchid plants by hydrolyzing it, and the orchid plants obtain an energy source by receiving carbon from them, creating a win-win relationship (Yamato and Tanigame, 2009). However, since hydrolyzing cellulose means that the plant's body is being broken down, it's unclear whether it's truly a 100% win-win situation.

This means that phalaenopsis orchids have a stage where they rely on other organisms for energy (heterotrophy) before they transition to the stage where they perform photosynthesis and obtain their own energy source (autotrophy).

Orchid species have evolved to specialize in obtaining energy through symbiosis with orchid mycorrhizal fungi, resulting in the loss of endosperm and cotyledons (Yamato and Tanigame, 2009; Yeung, 2017).

While many other symbiotic relationships between mycorrhizal fungi and plants are known, this is quite unique because, generally speaking, the mycorrhizal fungi obtain their energy source from the plant.

This type of relationship has been observed in many orchid species, and it is established between specific orchids and specific orchid mycorrhizal fungi.

On the other hand, conversely, this means that orchids cannot grow without orchid mycorrhizal fungi. This is thought to be the reason for their small population size, low tolerance to environmental changes, and difficulty in cultivation (Yamato and Tanigame, 2009).

But why do orchids rely on symbiosis with orchid mycorrhizal fungi in the first place?

Although I couldn't find any papers that explicitly state this, based on what I've considered so far, my conclusion is that because the parent plant doesn't need to store energy sources in the endosperm and cotyledons for the seed to develop initially, it has an advantage over other plants in certain environments, such as the presence of fungi, allowing for stable offspring development. On the other hand, it's likely that a disadvantage is that it may become unable to produce offspring if the environment changes.

References

Arai, Yoshiho; Ohro, Kohei; Koseki, Yoshiyuki; and Nagata, Junji. (2011). Dynamics of the Phalaenopsis orchid industry in Taiwan and international relay cultivation. E-journal GEO, 6 (1): 16-32. https://doi.org/10.4157/ejgeo.6.16

Shinichi Enoki. (2014). A study on highly efficient mass propagation of Phalaenopsis orchids using PSR medium and its application to molecular breeding. [Doctoral dissertation, Nagaoka University of Technology]. http://hdl.handle.net/10649/724

Fukunaga, Yuichi & Shimazaki, Kazuhiko. (2003). A survey on awareness regarding the conservation of wild plants and animals (mainly orchids). Journal of Biological Education, 43 (3): 127-138. https://doi.org/10.24718/jjbe.43.3_127

Miura, C., Saisho, M., Yagame, T., Yamato, M., & Kaminaka, H. (2019). Bletilla striata (Orchidaceae) seed coat restricts the invasion of fungal hyphae at the initial stage of fungal colonization. Plants, 8 (8): 280. https://doi.org/10.3390/plants8080280

Morimoto, Y., & Take, T., & Ikedo, T. (2016, January 20). Classification, evolution, and distribution of Phalaenopsis species. Cyber Wild-Orchid Mart. https://www.cyberwildorchid.com/products/phalaenopsis/Evolution/

Nishimura, Goro. (2004). A Cultural History of Flowers at Keisen University (1): Phalaenopsis Orchids. Bulletin of the Institute for Horticultural Culture, Keisen Women's University. Horticultural Culture, 1: 50-53. ISSN: 1882-5044, http://id.nii.ac.jp/1294/00000727/

Pramanik, D., Dorst, N., Meesters, N., Spaans, M., Smets, E., Welten, M., & Gravendeel, B. (2020). Evolution and development of three highly specialized floral structures of bee-pollinated Phalaenopsis species. EvoDevo, 11(1): 1-20. ISSN: 2041-9139, https://doi.org/10.1186/s13227-020-00160-z

Pridgeon, AM, Cribb, PJ, Chase, MW, & Rasmussen, FN (2014). Genera Orchidacearum (Vol. 6 Epidendroideae, Part 3). Oxford University Press. ISBN: 9780199646517

Phalaenopsis Station (February 21, 2025). The first company in Taiwan to establish a business in Phalaenopsis orchid production. https://ran-station.jp/?p=230

Tsukamoto, Yotaro. (1994). Encyclopedia of Horticultural Plants, Compact Edition. Shogakukan. ISBN: 9784093051118

Wu, ZY, Raven, PH, & Hong, DY (Eds.). (2009). Flora of China (Vol. 25 Orchidaceae). Science Press, and Missouri Botanical Garden Press. ISBN: 9781930723900

Yamato, Masahide & Tanigame, Takahiro. (2009). Symbiosis between orchids and fungi. Bulletin of the Mycological Society of Japan, 50 (1): 21-42. ISSN: 0029-0289, https://doi.org/10.18962/jjom.jjom.H20-02

Yeung, EC (2017). A perspective on orchid seed and protocorm development. Botanical Studies, 58 (1): 1-14. ISSN: 1817-406X, https://doi.org/10.1186/s40529-017-0188-4

Yoshimura, Yasuyuki. (2021). CAM plants distributed in Japan and their habitats. Journal of the Crop Science Society of Japan, 90 (3): 277-299. https://doi.org/10.1626/jcs.90.277

Source

This article is a significantly expanded version of a piece originally published in the following book.