Both Glechoma hederacea and Glechoma hederacea (European Glechoma) belong to the genus Glechoma in the Lamiaceae family. Their names, meaning "through the fence," come from the way their stems creep along the ground and pass through fences. They are characterized by kidney-shaped leaves and labiate flowers with a large opening in the center. Recently, Glechoma hederacea, which is cultivated in horticulture, has been confused with Glechoma hederacea. However, they have different origins and morphological differences, such as the size of the corolla and calyx. They are also sometimes confused with Centella asiatica, Lamium amplexicaule, and Mazus pumilus, but the distinctions are relatively easy. This article will explain the classification and morphology of the genus Glechoma hederacea.

What are Glechoma hederacea and Glechoma hederacea (European Glechoma)?

Glechoma hederacea subsp. grandis, also known as Kakidoshi (fence-piercing grass), is a perennial herb distributed in Japan from Hokkaido to Kyushu, southeastern China, and Taiwan, growing in fields and roadsides (Hayashi et al., 2013; RBG Kew, 2025). In China and the UK, its scientific name is Glechoma grandis.

Glechoma hederacea subsp. hederacea, commonly known as European ground ivy (Glechoma), is a perennial herb distributed in Europe, Russia, and Xinjiang, China, and has been introduced worldwide. It grows in valley meadows. In Japan, it is cultivated as an ornamental plant. In China and the UK, its scientific name is Glechoma hederacea.

Both belong to the genus Glechoma in the Lamiaceae family, and their name, "Kakidoshi" (meaning "through the fence"), comes from the way their stems creep along the ground and pass through hedges.

In addition to these features, its kidney-shaped flowers with blunt serrations, the distinctive lip-shaped flowers characteristic of the mint family with a gaping center, a large, protruding lower lip, and white hairs growing on the central side are also unique.

Many people are unaware that the true Glechoma hederacea and the "Glechoma hederacea" cultivated and sold in horticulture under the genus name Glechoma are different subspecies or even different species. The "Glechoma hederacea" currently cultivated in Japan is not a native species.

However, there doesn't seem to be any Japanese website that properly explains how to distinguish between them.

What is the difference between Glechoma hederacea and Glechoma hederacea (European Glechoma hederacea)?

Glechoma hederacea and Glechoma hederacea have different characteristics and are sometimes considered separate species overseas (Wu & Raven, 1994).

As a fundamental point, while Glechoma hederacea grows wild in Japan, Glechoma hederacea does not grow wild, and there is no evidence of it becoming naturalized; it is only cultivated.

Morphologically, one key difference is that the leaves of Glechoma hederacea are hairy, while those of Glechoma hederacea are hairless.

However, upon actually examining the images, the author found that European ground ivy also has hairs. It's just that European ground ivy has a glossier appearance and lacks the noticeable white hairs of common ground ivy, but that's about the only difference, and it's not entirely clear.

Furthermore, regarding the calyx of the flower, there is a difference in that the sepals of Glechoma hederacea are approximately 7-10 mm long, while those of Glechoma hederacea are 5-7 mm long.

Regarding the corolla of the flowers, there is a difference in size: in Glechoma hederacea, the corolla is large, measuring about 3 cm in length, while in Glechoma hederacea var. japonica, it is small, measuring about 1 cm in length.

Therefore, you will likely get the impression that the flowers of Glechoma hederacea are clearly larger and more conspicuous than those of Glechoma hederacea var. japonica. This is a more obvious difference.

Most variegated seedlings sold in garden centers appear to be European ground ivy (Glechoma hederacea subsp. grandis f. albovariegata). However, there are also variegated varieties of Japanese ground ivy, which are called variegated ground ivy (Glechoma hederacea subsp. grandis f. albovariegata). Those with white flowers are white ground ivy (Glechoma hederacea f. alboflorens).

What are the differences between Glechoma hederacea, Centella asiatica, Lamium amplexicaule, and Mazus pumilus?

The differences between Glechoma hederacea (Kakidōshi) and Lamium amplexicaule (Lamiaceae) , Mazus miquelii (Sudareaceae), and Centella asiatica (Apiaceae) are frequently searched for.

This is likely because *Lamium amplexicaule* and *Centella asiatica* are similar to *Glechoma hederacea* in that they have kidney-shaped leaves, while *Mazus pumilus* is similar to *Glechoma hederacea* in that its flowers are somewhat similar.

However, in terms of classification, they are quite different.

Unlike Glechoma hederacea, Lamium amplexicaule has short petioles on its upper leaves, and its flowers are small and tubular.

What are the differences between Lamium amplexicaule, Lamium purpureum, and Lamium album? How do they differ from Lamium album? We'll explain how to distinguish between similar species! Why are the fruits carried by ants?

Lamium amplexicaule, Lamium purpureum, and Lamium purpureum are all herbaceous plants belonging to the genus Lamium in the Lamiaceae family. Lamium amplexicaule and Lamium purpureum are particularly well-known as spring weeds, but some people may have trouble distinguishing between the three species. These three species are relatively easy to identify, and their leaves alone...

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Unlike Glechoma hederacea, the lower lip (the lower part of the flower) of the labiate flower of Mazus pumilus is not divided into two but is a single lobe. The leaves are obovate or circular.

Unlike Glechoma hederacea, Centella asiatica has a four-angled stem, coarse short hairs only on the ridges, and lacks glandular dots on the underside of the leaf blade. Its flowers are very small and inconspicuous.

References

Hayashi, Yasaka, Kadota, Yuichi, and Hirano, Takahisa. 2013. Yamakei Handy Illustrated Guide 1: Wildflowers (Revised and Expanded New Edition). Yama-kei Publishers, Tokyo. 664pp. ISBN: 9784635070195

RBG Kew. 2025. The International Plant Names Index and World Checklist of Vascular Plants. Plants of the World Online. http://www.ipni.org and https://powo.science.kew.org/

Wu, ZY, & Raven, PH (Eds.). 1994. Flora of China (Vol. 17 Verbenaceae through Solanaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis. 342pp. ISBN: 9780915279241

Both Angelica dahurica and Angelica pubescens belong to the Angelica genus of the Apiaceae family. They are medium to large perennial herbs with thick stems and broad leaves, and are similar in that their leaflets are large and rounded. However, upon closer observation, there are differences in their leaves, flowers, and fruits. However, since there are many species in the Angelica genus, careful distinction is necessary. The sheath at the base of the inflorescence is an important distinguishing feature. Angelica dahurica has the unusual characteristic of having purple flowers, and research suggests that this may be related to the fact that yellow jackets are attracted to its flowers. This article will explain the classification, morphology, and ecology of the Angelica genus.

What are Nodake and Shishiudo?

Angelica decursiva, also known as wild bamboo, is distributed in Honshu (west of the Kanto region), Shikoku, and Kyushu in Japan; as well as in Korea, China, and Eastern Siberia. It is a perennial herb that grows in woodlands and forest edges, excluding alluvial plains (Kanagawa Prefecture Flora Survey Association, 2018). Its Japanese name comes from the fact that it grows in the wild and the sheaths at the base of its leaves and inflorescences resemble the skin of young bamboo shoots (takenoko).

Angelica pubescens var. pubescens, also known as wild angelica, is a perennial herb distributed throughout Honshu, Shikoku, and Kyushu in Japan, growing in forest edges and grasslands throughout the region except for alluvial plains.

Both are medium to large perennial herbs belonging to the genus Angelica in the family Apiaceae, characterized by thick stems and broad leaves. The leaf, flower, and fruit structures, typical of the Apiaceae family, are all very similar. The fruits, in particular, are similar, both being flattened, hairless, and possessing somewhat broad, membranous wings.

Furthermore, you might notice similarities within the Angelica genus, such as the swollen, pouch-like base of the petiole and the large, rounded leaflets (the parts of a single leaf that have separated).

What is the difference between Nodake and Shishiudo?

Since there are many known species in the genus Angelica, distinguishing between only two species may not always be sufficient. However, when limited to just two species, the following differences can be observed (Kanagawa Prefecture Flora Survey Association, 2018).

Regarding the leaves, in Angelica dahurica, the underside of the leaf blade is hairless, and the base of the leaflets is wing-like, lacking petioles. In contrast, in Angelica pubescens, the veins on the underside of the leaf blade are covered with many curled fine hairs, and the base of the leaflets is wing-like, with some lacking petioles and others not wing-like but with petioles.

Regarding the flowers, in *Angelica acutiloba*, the petals are usually dark purple (although in the variety *Angelica acutiloba f. albiflora*, they are white) and have bracts, while in *Angelica pubescens*, the petals are white and there are no bracts.

The term "involucral bracts" may be unfamiliar, but it refers to the thin, leaf-like green structures that grow at the base of the pedicel (the slender part connecting the flower to the plant body), and is found in some species of the Apiaceae family. In Angelica dahurica, you can see thin, green, leaf-like structures mixed in with the flowers.

Regarding the fruit, both are flattened and hairless, with somewhat broad, membranous wings. However, in Angelica dahurica, the wings are only on the sides of the main body that encloses the seeds, whereas in Angelica pubescens, the wings are not only on the sides of the main body but also on the side where the pedicels are located.

Another important point is that *Angelica acutiloba* has a sheath (botanically speaking, a green, sac-like petiole with a reduced leaf blade) at the base of the inflorescence, while other *Angelica* species, including *Angelica pubescens*, either lack this sheath or have withered it. If you can confirm this point, it can be considered a decisive difference.

Are there any other similar species?

As mentioned above, there are many known species in the genus Angelica, so it may be necessary to consult a field guide to make precise distinctions.

Angelica japonica resembles Angelica dahurica, but the base of its leaflets is not wing-shaped, and its flowers are white.

Angelica hakonensis also resembles Angelica dahurica, but its leaves are 2-3 times pinnately compound, the leaflets have coarsely double-serrated margins, and its flowers are pale green (in Angelica dahurica, the leaves are 1-2 times pinnately compound, and the leaflets have low, simple-serrated margins).

For information on how to distinguish between other species in the Angelica genus, please see our other article.

What are the differences between Angelica keiskei, Angelica pubescens, and Angelica japonica? We'll explain how to distinguish between similar species! What are the structures of their flowers and fruits?

Angelica keiskei, Angelica pubescens, and Angelica japonica all belong to the Angelica genus of the Apiaceae family and are medium to large perennial herbs with thick stems and broad leaves. They all share similar leaf, flower, and fruit structures, characteristic of the Apiaceae family. Furthermore, the swollen, sac-like base of the petiole and the flattened fruit are typical features of this group...

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How is pollination done?

The flowering period of Angelica dahurica is from September to November. The compound umbels are dense, there are no sepals, and the petals are dark purple, rarely white (in the case of Angelica dahurica var. alba) (Hayashi et al., 2013).

This flower is particularly distinctive for its purple petals, but do insects visit and pollinate it?

Recent studies that have actually examined pollinating insects alongside *Leucothoe gracilis* have yielded interesting findings (Mochizuki, 2024).

This study confirmed that 14 species of insects visit Angelica dahurica, but 62% were yellow hornets (Vespa simillima). Similarly, yellow hornets were the majority of visitors to Rock Carrot (Leucanthemum boreale). Furthermore, it was confirmed that pollen adheres to the bodies of the yellow hornets, confirming their contribution to pollination.

However, these yellow jacket wasps have not only been observed feeding on nectar, but also hunting other pollinating insects. Therefore, this symbiotic relationship may differ from typical symbiotic relationships between insects and nectar-producing insects.

This is an interesting case because it is rare to find hunting wasps like the yellow jacket playing a major role in flower pollination.

Some theories suggest that the dark purple color of the petals of Angelica dahurica and the green color of the petals of Rock Carrot are adaptations to attract wasps. Differences in flower color between different genus Angelica and between different species of Angelica may also be influenced by these differences in pollinating insects, and further research may reveal more details.

References

Hayashi, Yasaka, Kadota, Yuichi, and Hirano, Takahisa. 2013. Yamakei Handy Illustrated Guide 1: Wildflowers (Revised and Expanded New Edition). Yama-kei Publishers, Tokyo. 664pp. ISBN: 9784635070195

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

Mochizuki, K. 2024. Hunt and pollinate: Hornet pollination of the putative generalist genus Angelica. Ecology e4311. https://doi.org/10.1002/ecy.4311

Dill and fennel both belong to the Apiaceae family, possess a strong aroma throughout the plant, and are used in both ways: their leaves are used as herbs, and their fruits as spices. Their leaves, in particular, are known as "fish herbs" and pair exceptionally well with fish dishes. Furthermore, their morphological similarities can easily confuse them. However, upon closer inspection, differences in the leaves, petioles, stems, and fruits allow for differentiation. While their uses are largely the same, dill has a stronger acidity, while fennel is sweeter, leading to different uses depending on the preference. This article will explain the classification, morphology, and uses of dill and fennel.

What are dill (yin-dill) and fennel (uyn-yen)?

Anethum graveolens, also known as dill, coriander, or parsley, is an annual plant native to West Asia and North Africa. It has been cultivated in Europe, North Africa, and Asia since ancient times and is now cultivated all over the world.

Feniculum vulgare, also known as fennel or finocchio, is a perennial plant native to the Mediterranean region of Europe, North Africa, West Asia, and parts of Central Asia. Bronze fennel 'Purpureum' is a horticultural variety with copper-colored leaves.

Both belong to the Apiaceae family, and the entire plant has a strong aroma. Both plants are used as herbs (leaves) and spices (fruits). The leaves, in particular, are known as "fish herbs" and pair exceptionally well with fish dishes.

Morphologically, they share the common characteristics of having pinnately compound leaves that are completely divided into thread-like structures, and yellow petals.

The fruits are very similar, and are sold under the names "dill seeds" for dill and "fennel seeds" for fennel. However, they are actually "fruits," not "seeds." The true seeds are much smaller and exist inside.

For these reasons, many people may not understand the difference between the two types.

What is the difference between dill and fennel?

The difference between dill and fennel can be a bit tricky, but there are several differences (Wu et al., 2005).

First of all, in terms of classification, dill belongs to the genus Alanthus, while fennel belongs to the genus Foeniculum, so there is quite a difference between them.

Regarding the leaves, dill has short, less deeply lobed pinnately compound leaves, making it appear relatively sparse, while fennel has long, more deeply lobed pinnately compound leaves, making it appear relatively dense.

Regarding the stems, dill has green leaves, while fennel has grayish-green stems.

Regarding the roots, while dill has a common, unremarkable leaf stalk, a variety of fennel, specifically Florence fennel (Italian fennel, sweet fennel) Foeniculum vulgare Azoricum Group (synonym: Foeniculum vulgare var. dulce), differs in that its leaf stalks are pure white, swollen like a sheath, and enclose the stem. This is called a "bulb," similar to those found in celery and onions.

Regarding the flowers, dill has more flowers per inflorescence and blooms more densely.

Regarding the fruits (dill seeds and fennel seeds), dill seeds are generally oval-shaped, flattened, and have long stalks, while fennel seeds are generally oblong-shaped, somewhat thicker, and have shorter stalks.

However, since the fruits of the Apiaceae family are all very similar, it's best not to easily determine the species from between the two when looking at living plants.

What are the differences in how dill and fennel are used?

Are there any differences in the uses of dill and fennel?

Dill has been used since ancient times, with evidence of its discovery in the tomb of Amenhotep II, a king of ancient Egypt (New Kingdom) around 1400 BC (Prance & Nesbitt, 2005). Originally, it was highly valued as a medicinal herb for treating indigestion, and its leaves, fruit (dill seeds), and essential oil were used. Although it is not very well known in Japan, it is widely used mainly in Europe and Asia across the Eurasian continent.

Nowadays, dill is commonly used as a herb (dill weed) and a spice (dill seeds). Dill weed is characterized by its sour and bitter taste and is widely used in dishes such as marinades, dressings, and soups. It pairs well with meat dishes as well as fish dishes such as smoked salmon and herring, earning it the nickname "fish herb." Dill seeds have a mild spiciness and are used as a spice and in pickling liquids.

On the other hand, fennel has also been used since ancient times, and it appears in Greek mythology, indicating that it was used by the ancient Greeks and Romans for medicinal, culinary, and insect-repellent purposes. Although it is not very familiar in Japan, it is widely used mainly in Europe and Asia across the Eurasian continent.

Nowadays, it's common to use the herb, fennel seeds, and bulbs for food. The herb has a sweet and spicy aroma with a hint of bitterness and is used to flavor salads and pickles, as well as in soups and fish dishes. Fennel seeds have a refreshing, sweet aroma and are used as a spice in curries and Chinese cuisine, as well as in cookies, scones, and other sweets.

One difference between fennel and dill is that Florence fennel uses its bulb as a vegetable. It has a crisp texture and can be sautéed, stewed, grilled, or eaten raw.

In summary, dill and fennel are used in almost the same way, but they differ slightly in taste and whether or not they are used as vegetables. The specific dishes in which they are used may also vary from country to country.

References

Prance, G., & Nesbitt, M. 2005. The Cultural History of Plants. Routledge, London. 460pp. ISBN: 9780415927468

Wu, ZY, Raven, PH, & Hong, DY (Eds.). 2005. Flora of China (Vol. 14 Apiaceae through Ericaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis. ISBN: 9781930723412

Angelica keiskei, Angelica pubescens, and Angelica japonica all belong to the Angelica genus of the Apiaceae family and are medium to large perennial herbs with thick stems and broad leaves. The structure of their leaves, flowers, and fruits is very similar, which is characteristic of the Apiaceae family. Furthermore, the swollen, sac-like base of the petiole and the flattened fruit are typical features of this group. However, they can be distinguished by checking the amount of hair on the leaves and the presence or absence of involucral bracts. The flowers, which are composed of umbels, are small and undergo sex change. The fruit is a schizocarp, flattened, and has a membranous, somewhat broad wing. This article will explain the classification and morphology of Angelica keiskei, Angelica pubescens, and Angelica japonica.

What are Ashitaba, Shishiudo, and Hamaudo?

Angelica keiskei, also known as Ashitaba or Shii-gusa, is a perennial herb that grows along the coast and is distributed in Honshu (southern Kanto region, Izu Islands, Tokai region, Kii Peninsula) and the Ogasawara Islands of Japan (Kanagawa Prefecture Flora Survey Association, 2018; Ohashi et al., 2017).

Angelica pubescens var. pubescens, also known as wild angelica, is a perennial herb distributed throughout Honshu, Shikoku, and Kyushu in Japan, growing in forest edges and grasslands throughout the region except for alluvial plains.

Angelica japonica, also known as beach angelica, is a perennial herb that grows along the coast and is distributed in Honshu (west of the Kanto region), Shikoku, Kyushu, and the Ryukyu Islands in Japan, as well as in Korea (Kanagawa Prefecture Flora Survey Association, 2018; Hayashi et al., 2013).

Both are medium to large perennial herbs belonging to the Angelica genus of the Apiaceae family, characterized by thick stems and broad leaves. The leaf, flower, and fruit structures, which are typical of the Apiaceae family, are all very similar.

All species in the genus Angelica share the common trait of having flattened, hairless fruits with somewhat broad, membranous wings. Furthermore, the three species mentioned above are particularly similar in that the stalks of their large umbel inflorescences are covered with short hairs or hair-like projections, either entirely or internally, and the base of the petiole is swollen and sac-like. Therefore, identification can sometimes be difficult.

What are the differences between Ashitaba, Shishiudo, and Hamaudo?

There are 23 species of Angelica native to Japan, and it's impossible to cover all of them here, but let's consider the three species mentioned earlier.

First, Angelica pubescens lacks involucral bracts and has many curled fine hairs on the veins of the underside of the leaves, whereas Angelica keiskei and Angelica japonica have involucral bracts and the underside of the leaves is hairless.

The term "involucral bracts" may be unfamiliar, but they are thin, leaf-like green structures that grow at the base of the pedicel (the slender part connecting the flower to the plant body), and they can be found in some species of the Apiaceae family. In Angelica keiskei and Angelica japonica, you can see thin, green, leaf-like structures mixed in with the flowers.

Regarding Angelica keiskei and Angelica japonica, the main difference is that Angelica keiskei has almost no hairs on the midrib on the upper surface of the leaf and on the upper surface of the leaf axis, while Angelica japonica has dense short hairs on the midrib on the upper surface of the leaf and on the upper surface of the leaf axis.

Other differences include the fact that Angelica keiskei has thick leaves, releases a yellow sap when the stem is cut, and has pale yellowish-green flowers, while Angelica japonica does not have particularly thick leaves, has white flowers, and does not release a yellow sap when the stem is cut.

Incidentally, Angelica matsumurae, a variety of Angelica shikokiana, has hairless stems.

This allows you to distinguish between the three species, but be aware that if you are judging purely by shape, you will also need to distinguish them from other species such as Angelica dahurica, Rock ginseng, Angelica shikokiana, and Angelica acutiloba. For more detailed information, please refer to the Kanagawa Prefectural Flora Survey Association (2018) or Ohashi et al. (2017).

Are there any other similar species?

As mentioned above, many species of the Angelica genus grow wild in Japan.

For information on the differences between Nodake and Shishiudo, please see our separate article.

What's the difference between Angelica acutiloba and Angelica gigas? We'll explain how to distinguish between similar species! Is the purple color of the flowers due to wasps?!

Both Angelica dahurica and Angelica pubescens belong to the Angelica genus of the Apiaceae family. They are medium to large perennial herbs with thick stems and broad leaves, and are similar in that their leaflets are large and rounded. However, upon closer observation, there are differences in their leaves, flowers, and fruits. However, since there are many species in the Angelica genus, careful distinction is necessary...

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What is the structure of a flower?

Like many other members of the Apiaceae family, the flowers form umbels.

After the stamens and petals have formed, they fall off, and the pistil develops. A structure common to the Apiaceae family (Shimizu, 2001) called the "columnar base" or "columnar base," which is a glossy structure that secretes nectar and is part of the pistil, develops. My photo shows the later stage.

This process, where the stamens appear first and then the pistils appear, is called "protandry," and it is observed in some species of the Apiaceae family, preventing self-pollination (Watanabe, 1999).

Angelica keiskei flowers from August to October. Its compound umbels lack involucral bracts, but have several involucral bracts. It bears pale yellow flowers and lacks sepals.

Angelica pubescens flowers from August to November. It bears numerous small white flowers in large umbel-shaped inflorescences. The stalks of the umbel-shaped inflorescences are irregularly shaped, ranging in length from 3 to 18 cm. There are no involucral bracts or involucral bracteoles. The petals are numbered 3 to 5, with two lobes at the tip, slightly curved inward, and sometimes tinged with yellow.

Japanese angelica tree (Hamaudo) blooms from April to June. Compound umbels emerge from the tips of its branches, bearing dense clusters of small white flowers. The involucral bracts at the base of the pedicels and the involucral bracts at the base of the pedicels are both elongated.

What is the structure of the fruit?

The fruit, like many species in the Apiaceae family, is a schizocarp. A schizocarp is a type of dehiscent fruit, consisting of multiple carpels. When mature, the number of schizocarps corresponds to the number of carpels, and the fruit splits open, separating from the central axis. This type of fruit is widely found in the Apiaceae family.

Common to all species in the Angelica genus, the fruit is flattened, hairless, and has a membranous, somewhat broad wing.

The fruit of Angelica keiskei is oblong, with relatively narrow wings. It consists of two flattened carpels joined together. There is one oil duct under each dorsal groove and four on the fused surface. The wing-like portion of the carpel is not as wide as that of Angelica japonica.

The fruit of Angelica pubescens is 7–9 (up to 11) mm long and 5–7 mm wide, with broad wings and consisting of two flattened segments joined together. The oil glands on the surface of the fruit are clearly visible.

The fruit of Angelica japonica is flattened and broadly oval, consisting of two flattened carpels joined together. The carpels are oblong, with broad, wing-like ridges on both sides, giving them a fan-like appearance.

References

Hayashi, Yasaka, Kadota, Yuichi, and Hirano, Takahisa. 2013. Yamakei Handy Illustrated Guide 1: Wildflowers (Revised and Expanded New Edition). Yama-kei Publishers, Tokyo. 664pp. ISBN: 9784635070195

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

Ohashi, Hiroyoshi; Kadota, Yuichi; Murata, Hitoshi; Yonekura, Koji; and Kihara, Hiroshi. 2017. Wild Plants of Japan (Revised New Edition, Vol. 5: Convolvulaceae to Caprifoliaceae). Heibonsha, Tokyo. 760pp. ISBN: 9784582535358

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

Watanabe, Osamu. 1999. Illustrated Key to Major Apiaceae Plants in Hokkaido, Part 1: Large Species - Plants Identified by Leaves 2. Shiretoko Museum Research Report 20: 15-32. ISSN: 0387-8716, https://shiretoko-museum.jpn.org/media/shuppan/kempo/sm20_02.pdf

Both Torilis japonica and Torilis japonica are biennial herbs belonging to the genus Torilis in the family Apiaceae, and are extremely common in Japan, growing in grasslands, thickets, and roadsides. These two species grow in similar environments, their flowers and fruits are very similar, and both have leaves that are 2-3 times pinnately compound. Therefore, it is often difficult to distinguish between them. However, there are considerable differences when examined closely. The easiest difference for me to spot is the number of pedicels attached to the inflorescence axis and the number of pedicels attached to the pedicels. Investigating the color of the bristles on the ovary and the flowering period can also be important clues. Like many species in the Apiaceae family, they form compound umbels, and the flowers are white and have a relatively simple structure. Based on the structure of the flowers, it seems that there would be a wide variety of visiting insects, but data shows that bees tend to be the most frequent visitors. The fruit, like many species in the Apiaceae family, is a dichocarp, with a unique structure in which one immature fruit splits into two schizocarps that hang from the left and right. The fruit segments are covered with numerous hook-shaped bristles, and as the Japanese name suggests, they disperse by attaching to human clothing or animal furs like lice. However, recent research suggests they can also be carried by ocean currents. This article will explain the classification, morphology, pollination ecology, and seed dispersal of the genus *Torilis*.

What are the Japanese bush louse and the large bush louse?

Torilis japonica, also known as bush louse, is distributed in Hokkaido, Honshu, Shikoku, Kyushu, and the Ryukyu Islands in Japan; and in temperate to tropical regions of Asia, Europe, and North America. It is a biennial herb that grows in grasslands, thickets, and roadsides (Kanagawa Prefecture Flora Survey Association, 2018). The North American population is an invasive species (DiTommaso et al., 2014).

Torilis scabra, also known as the male bush louse, is distributed in Honshu, Shikoku, Kyushu, and the Ryukyu Islands of Japan; as well as in Korea, China, and Taiwan. It is a biennial herb that grows in grasslands, thickets, and roadsides.

Both are biennial plants belonging to the genus Torilis in the family Apiaceae, and in Japan, they grow in almost the same environments.

The most distinctive feature of these two species is that their fruits are "burrs." The Japanese name "Yabujirashi" (藪虱) comes from the fact that they grow in bushes, and their fruits have hook-shaped, curved bristles that make them difficult to remove once they stick to clothing, likening them to the human louse, an insect that clings to the skin. While other Apiaceae species also have hairy fruits, only the genus Torilis in Japan has such dense, rough-surfaced hairs.

However, the two species are very similar, and you may have trouble distinguishing them. Their flowers are almost identical, and both have leaves that are 2-3 times pinnately compound.

What is the difference between *Limbucus japonica* and *Limbucus ventricosus*?

There are many differences between these two types, but because their structures are complex, it's difficult to describe them in a single sentence. That's why I used to get confused about them too. But now I can clearly see the differences.

What I find easiest to understand is the difference between the number of "pedicels" attached to the pedicels of an umbel and the number of "pedicels" attached to the inflorescence axis (Hayashi et al., 2013; Kanagawa Prefectural Flora Survey Association, 2018).

A pedicel is a short stalk that supports a flower, while a pedicel is the stalk that supports the entire cluster of pedicels. The inflorescence axis is the stalk that supports the entire pedicel. Looking at it from the other side, it branches out from the inflorescence axis → pedicel → pedicel, ultimately resulting in a single flower. In an umbel, pedicels of equal length radiate from the inflorescence axis.

In *Torilis japonica*, the number of pedicels attached to a single flower stalk is large, ranging from 4 to 10 or more, and the pedicels are short, whereas in *Torilis japonica*, the number is small, ranging from 2 to 5, and the pedicels are long.

Furthermore, there is a difference in the number of pedicels per inflorescence axis: 5 to 9 or more in *Torilis japonica*, compared to 2 to 5 in *Torilis japonica*.

It's difficult to describe in words, but I think it's immediately obvious when you see a photograph. Roughly speaking, when viewed from a distance, you'll get the impression that the flowers of *Torilis japonica* are quite densely packed, while those of *Torilis japonica* are quite sparsely packed.

There are many other differences as well.

While the petals of *Torilis japonica* often have a reddish tint, the hairs on the ovary are usually not reddish. However, in *Torilis japonica*, both the petals and ovary are often a deeper purplish-red. This can be a significant distinguishing feature, but it doesn't necessarily mean that *Torilis japonica* always has this coloration.

In *Torilis japonica*, the petioles of the leaflets are short, but in *Torilis japonica*, the petioles of the leaflets are long.

In *Torilis japonica*, the involucre has 4 to 6 bracts and the flowering period is from June to mid-August, while in *Torilis japonica*, the involucre has 0 to 2 bracts and the flowering period is from late April to May. In some regions, the flowering periods may overlap.

In *Torilis japonica*, the fruit is oval-shaped, 4-5 mm long, and the bristles grow irregularly. In *Torilis japonica*, the fruit is oblong-oval-shaped, 6-8 mm long, and the bristles grow in rows.

In addition, the Japanese genus *Torilis* also includes * Torilis leptophylla*, which grows to a height of less than 40 cm, and the climbing species *Torilis nodosa*, but these are rare introduced species and are unlikely to be seen.

What is the structure of a flower?

Like many plants in the Apiaceae family, the genus Torilis has compound umbels. Therefore, you will notice that the flowers are arranged in a regular, radial pattern. At this stage, you can already see dense bristles on the ovary of the flower.

Torilis japonica flowers from June to mid-August. It produces small compound umbels at the tips of its branches, bearing small white flowers. Each inflorescence axis has 2 to 5 pedicels, and each pedicel has 4 to 10 or more pedicels. The flowers have 5 petals, the outer ones of the inflorescence being larger. The edges of the petals are tinged with purple. The involucral bracts are 4 to 6 in number and are elongated.

Torilis japonica flowers from late April to May. It produces small compound umbels at the tips of its branches, bearing small white flowers. Each inflorescence axis has 5 to 9 pedicels, and each pedicel has 2 to 5 pedicels. The petals are all nearly homologous, hairy on the back, and the petals and ovary are often tinged with dark purplish-red. There are 0 to 2 bracts in the involucre.

How is pollination done?

According to a study conducted in Nara Prefecture, approximately 60% of the insects that visit the flowers of the Japanese bush louse (Torilis japonica) are bees, and about 20% are wasps (Yokoi et al., 2008). The remaining visitors are small amounts of other Hymenoptera, hoverflies, and flies.

Furthermore, studies that have examined specific species have confirmed that bees such as Lasioglossum occidens (medium-sized, short tongue) and Ceratina iwatai (small, short tongue) visit the area (Negoro, 1999).

Therefore, it seems highly likely that small to medium-sized bees and wasps with short proboscises are contributing to pollination. The flower structure is simple, so it's easy to predict that insects with short mouths will visit it, but this is an interesting contrast to the Bupleurum genus, which has yellow flowers and belongs to the same Apiaceae family, and is therefore preferred by flies.

What are the differences between Bupleurum falcatum and Bupleurum chinense? We'll explain how to distinguish between similar species! Why are they used in traditional Chinese medicine? Why are they endangered? Do flies come to the flowers to lick the nectar?

Bupleurum falcatum and Bupleurum chinense are both yellow-flowered plants belonging to the Apiaceae family that grow in sunny grasslands, so it can be difficult to distinguish between them. The difference lies in whether the base of the stem leaves clasps the stem or not. While it may not be possible to distinguish them by the shape of the flowers, there are differences in the shape of the involucral bracts...

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I could not find any research on the insects that visit the flowers of *Torilis japonica*. The flower structure is almost the same as that of *Torilis japonica*, so there are probably not many differences, but since the flowering periods are different, the species that visit the flowers may be different.

What is the structure of the fruit?

The genus Torilis is a common species of dichocarp found in the Apiaceae family (Shimizu, 2001). Dichocarps are a type of dry fruit that is both cleistogamous (indehiscent) and schizocarp, with two schizocarps hanging from the apex of the fruit stalk.

This might be a little confusing, but to put it another way, a fruit that develops from a single flower splits into two when it ripens. Also, when it ripens, its color changes from green to brown.

The double syconium of *Torilis japonica* is oval-shaped, 4-5 mm long, and densely covered with uniformly distributed bristles that curve hook-shaped from the base to the tip. The main ridge is very thin and almost smooth.

The double cusps of *Torilis japonica* are oblong, 6-8 mm long, with short, appressed white hairs similar in texture to the pedicel on the main ridge, and long, almost straight, hook-shaped bristles on the secondary ridge. The bristles appear to grow more regularly and straightly than those of *Torilis japonica*.

What are the seed dispersal methods?

As mentioned above, the hook-shaped bristles growing on the fruits of *Torilis japonica* and *Torilis japonica* are clearly for attaching to animal hair, and are therefore considered to be "burrs" that "disperse by attaching to animals" (Nakanishi, 1989; DiTommaso et al., 2014).

The fruit segments hanging from the top of the fruit stalk are also clearly adapted to easily come into contact with vertebrates passing by the bush lice.

In particular, individuals growing in grasslands, bushes, and roadsides with heavy human traffic can be assumed to reproduce almost entirely by attaching themselves to people's clothing.

However, it is still unclear and not well understood what kind of animals naturally dispersed the seeds in the wild.

Furthermore, recent research is revealing that, in addition to animal-attached dispersal, coastal populations also utilize "water current dispersal" (Nakanishi, 2020).

Air accumulates between the bristles and in the recessed areas where the fruit segments separate, creating buoyancy. However, the air gradually disappears, and it seems it cannot float indefinitely, so it's not entirely adapted to water spraying, but it's an interesting fact that demonstrates nature's flexibility.

References

DiTommaso, A., Darbyshire, SJ, Marschner, CA, & Averill, KM 2014. Japanese Hedgeparsley (Torilis japonica) — A New Invasive Species in the United States?. Invasive Plant Science and Management 7: 553-560. https://doi.org/10.1614/IPSM-D-14-00028.1

Hayashi, Yasaka, Kadota, Yuichi, and Hirano, Takahisa. 2013. Yamakei Handy Illustrated Guide 1: Wildflowers (Revised and Expanded New Edition). Yama-kei Publishers, Tokyo. 664pp. ISBN: 9784635070195

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

Nakanishi, Hiroki. 1989. Morphology and attachment of animal-attached dispersal bodies. Phytogeography and Taxonomy 37(1): 57-63. http://doi.org/10.24517/00055987

Nakanishi, Hiroki. 2020. Growth status and ocean current dispersal of three inland plant species growing on the coast. Journal of the Japan Society for Driftwood 18: 7-12. https://doi.org/10.57279/driftological.18.0_7

Negoro, Takashi. 1999. Flower-visiting behavior of bees at Kanazawa Castle Ruins (former Kanazawa University campus). Research Report of Toyama City Science and Culture Center 22: 55-79. ISSN: 0387-9089, http://repo.tsm.toyama.toyama.jp/?action=pages_view_main&active_action=repository_view_main_item_detail&item_id=731&item_no=1&page_id=13&block_id=82

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

Yokoi, Tomoyuki; Habe, Akifumi; Katori, Ikuo; and Sakuraya, Yasuyuki. 2008. Diversity of pollinating insect communities at Kinki University Nara Campus. Kinki University Faculty of Agriculture Bulletin 41: 77-94. ISSN: 0453-8889, http://id.nii.ac.jp/1391/00005214/

Bupleurum falcatum and Bupleurum chinense are both yellow-flowered plants belonging to the Apiaceae family that grow in sunny grasslands, so it can be difficult to distinguish between them. The difference lies in whether the base of the stem leaves clasps the stem or not. It seems that they cannot be distinguished by the morphology of the flowers, but there appears to be a difference in the shape of the involucral bracts. Bupleurum falcatum is also cultivated because its roots have medicinal properties. The roots, known as "Saiko" in traditional Chinese medicine, have been used as a psychotropic, anti-inflammatory, pus-draining, and tonic drug. However, due to its medicinal use, most of the wild plants in Japan have been overharvested, and it has gone from an endangered species to an extinct one in Japan. Currently, cultivated plants in Japan and wild individuals from Korea and China are used. Bupleurum flowers have a well-developed structure called the "columnar base" or "columnar base," which is part of the pistil, and is glossy and secretes nectar. Although there is insufficient research on this flower, it is highly likely that it is mainly visited by flies with short mouths that prefer yellow flowers. This article will explain the classification, medicinal uses, history, and pollination ecology of Bupleurum falcatum and Bupleurum chinense.

A yellow-flowered plant belonging to the Apiaceae family that grows in sunny grasslands.

Bupleurum stenophyllum, also known as Mishima-saiko, is a perennial herb distributed in Honshu, Shikoku, and Kyushu in Japan; the Korean Peninsula; Siberia; Amur; Ussuri; Sakhalin; Mongolia; Northeast China; and Europe, inhabiting sunny grasslands from hills to mountains (Kyoto Prefectural Government, Department of Environment, Natural Environment Conservation Division, 2015). Its name originates from the fact that high-quality herbal medicine materials were produced in Mishima, Shizuoka Prefecture.

Bupleurum longiradiatum, also known as firefly bud lily, is a perennial herb distributed in Hokkaido, Honshu, Shikoku, and Kyushu in Japan, as well as in Sakhalin and Ussuri. It is found scattered in bright forests and grasslands on plateaus and hills. Its name is said to come from the resemblance of its yellow flowers to the light of fireflies, but this is not a characteristic unique to firefly bud lily.

Both belong to the genus Bupleurum in the family Apiaceae, and their flowers are yellow, making them very similar. Their habitats are also similar, so it may be difficult to distinguish them. The involucral bracts (leaf-like structures that emerge from the base of the inflorescence) are ovate to narrowly elliptical and hairless, which is a major characteristic of the genus Bupleurum and distinguishes it from other genera in the Apiaceae family.

What is the difference between Mishima Saiko and Hotaru Saiko?

Bupleurum falcatum and Bupleurum chinense can generally be distinguished by the base of their stems and leaves.

Specifically, in Bupleurum falcatum, the base of the stem leaves does not clasp the stem, and the width of the upper stem leaves is less than 2 cm, whereas in Bupleurum chinense, the base of the stem leaves clasps the stem, and the width of the upper stem leaves is 2 cm or more.

While I was unable to confirm the differences in the flowers themselves, it appears that the involucral bracts are nearly lanceolate in Bupleurum falcatum, while they are narrowly elliptical in Bupleurum chinense.

In addition, other species such as Bupleurum nipponicum and Bupleurum ajanense also exist in Japan, but they are omitted here due to their limited distribution.

Bupleurum fontanesii, a naturalized species native to the Mediterranean coast, is distinguished from two other species by the fact that its involucral bracts are longer than its inflorescences.

Furthermore, Bupleurum rotundifolium, a naturalized species native to West Asia, is distinguished from the other two species by its stems and leaves that pierce the stem and are attached in a shield-like manner.

Why did the Mishima Bupleurum become an endangered species?

Bupleurum falcatum is cultivated because its roots have medicinal properties. The roots, known as Saiko in traditional Chinese medicine, are used as a psychotropic, anti-inflammatory, pus-draining, and tonic agent (Minami, 1995). It also has antipyretic, analgesic, and detoxifying effects, and is specifically used for alternating chills and fever during the middle stages of a cold, and for chest and flank discomfort. It is also effective for malaria, liver disease, and bilateral flank pain (pain and tightness in the armpits).

The main component responsible for this effect is thought to be saikosaponin af (Sasahara, 1992).

These effects were stronger in wild individuals, and they were considered superior (Minami, 1995). As a result, most of the plants growing wild in Japan were overharvested, and consequently, even those that once grew widely in the mountains and fields west of Ibaraki Prefecture have almost disappeared.

Therefore, their numbers remain very small, and in Japan, they are designated as Endangered Species II by the Ministry of the Environment (Kyoto Prefectural Government, Department of Environment, Natural Environment Conservation Division, 2015). They are also listed on some form of Red List in 32 prefectures, and in some prefectures, they have been deemed extinct (Wildlife Survey Association/Envision Environmental Conservation Office, 2023).

Although domestic production still takes place, it is mainly cultivated. Furthermore, due to price competition with inexpensive imports from China and South Korea, the volume of imports is increasing year by year (Minami, 1995). In 2008, of the approximately 444 tons of Bupleurum used, 23 tons (5%) were produced in Japan, while 399 tons (90%) were imported from China (Kaneko et al., 2013). However, it is important to keep in mind from a sustainability perspective that even these Chinese imports are from wild plants.

What is the structure of a flower?

Bupleurum falcatum flowers from August to October. It bears 5 to 10 small yellow flowers in compound umbels on the stem. The petals are 5 in number, about 2 mm in diameter, and curve inward at the tip. There are 5 stamens. The ovary is inferior. There are 1 to 3 involucral bracts. The involucral bracts are 5 in number and longer than the pedicel.

The flowering period of *Ipomoea purpurea* is from July to August. The flowers are arranged in compound umbels, with multiple small yellow flowers. The petals are 5 in number and about 3 mm in diameter. The involucral bracts and involucral bracts are narrowly elliptical, and the involucral bracts are shorter than the pedicels.

Both flowers initially have yellow stamens and petals, which then fall off, leaving the pistil. A glossy, nectar-secreting structure common to the Apiaceae family, called the "columnar base" or "columnar base" (Shimizu, 2001), develops as part of the pistil. My photos show the later stage.

This process, where the stamens appear first and then the pistils appear, is called "protandry," and it is observed in some species of the Apiaceae family, preventing self-pollination (Watanabe, 1999).

Based on research into closely related species, it's highly likely that flies are attracted to these flowers.

What kinds of insects visit these flowers?

Unfortunately, I couldn't find any research on these species in Japan, but there are some studies on Bupleurum bicaule, a member of the Bupleurum genus. Bupleurum bicaule is a perennial herb distributed in Afghanistan, South Korea, China, Mongolia, and Russia, growing on forest edges, gravel or sunny mountain slopes, and dry, stony grasslands.

A study conducted in the Mongolian steppes recorded that a species of parasitic fly , Deopalpus sp., was visiting flowers (Song, 2015).

Furthermore, studies conducted on the Mongolian steppes have shown that a species of hoverfly and a species of bee hoverfly visited the area (Yoshihara et al., 2008).

These records suggest that the nectar is coming from very shallow parts of the flower, so it's possible that flies with short mouths are the main visitors. Also, flies are thought to prefer yellow flowers.

In fact, using Google Image Search, I found two images showing a species of hoverfly visiting a Bupleurum falcatum plant.

These characteristics may not be unique to the Bupleurum genus, but could be widely observed in other members of the Apiaceae family that have yellow flowers. Therefore, there may not be any special ecological features unique to the Bupleurum genus.

However, as an endangered species, it will be necessary to properly investigate its relationship with pollinating insects in Japan.

Are the fruits schizocarps and the seeds dispersed by gravity?

The fruit is a schizocarp, a common feature in the genus Bupleurum. A schizocarp is a type of dehiscent fruit, consisting of multiple carpels. When mature, the number of schizocarps corresponds to the number of carpels, and the fruit splits open, separating from the central axis. This type of fruit is widely found in the Apiaceae family.

The fruitlets of Bupleurum falcatum are oval-shaped, brown, and about 3 mm long.

The fruitlets of Bupleurum falcatum are oblong, measuring 3.5 to 4 mm in length.

It is likely that it is dispersed by gravity, but I could not find any detailed research on this.

References

Kaneko, M., Tsukakoshi, S., Fujise, A., & Ikegami, F. 2013. Effects of nutrient solution concentration on the growth, saikosaponin concentration, and inorganic component concentration of Bupleurum falcatum L. in rockwool cultivation. Plant Environmental Engineering 25(2): 83-89. https://doi.org/10.2525/shita.25.83

Kyoto Prefectural Government, Department of Environment, Natural Environment Conservation Division. 2015. Kyoto Prefecture Red Data Book 2015 (Volume 2: Wild Plants and Fungi). Kyoto Prefectural Government, Department of Environment, Natural Environment Conservation Division, Kyoto. 611pp. https://www.pref.kyoto.jp/kankyo/rdb/index.html

Nam, Ki-tai. 1995. Developmental physiology of Bupleurum falcatum, a commonly used herbal medicine. Root Research 4(2): 52-55. ISSN: 0919-2182, https://doi.org/10.3117/rootres.4.52

Sasahara, Toshiya; Ito, Yasuyuki; and Katano, Manabu. 1992. Studies on the cultivation of Bupleurum falcatum (4): Root morphology and saikosaponin content. Bulletin of the Faculty of Agriculture, Kyushu Tokai University 11: 61-66. https://agriknowledge.affrc.go.jp/RN/2010471152

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

Song, DS 2015. Spatial and temporal variation in wild pollination service in the Mongolian steppe [Doctoral dissertation, University of Pennsylvania]. https://repository.upenn.edu/handle/20.500.14332/27924

Watanabe, Osamu. 1999. Illustrated Key to Major Apiaceae Plants in Hokkaido, Part 1: Large Species - Plants Identified by Leaves 2. Shiretoko Museum Research Report 20: 15-32. ISSN: 0387-8716, https://shiretoko-museum.jpn.org/media/shuppan/kempo/sm20_02.pdf

Wildlife Survey Association / Envision Environmental Conservation Office. January 15, 2023. Japan Red Data Search System. http://jpnrdb.com/

Yoshihara, Y., Chimeddorj, B., Buuveibaatar, B., Lhagvasuren, B., & Takatsuki, S. 2008. Effects of livestock grazing on pollination on a steppe in eastern Mongolia. Biological Conservation 141(9): 2376-2386. ISSN: 0006-3207, https://doi.org/10.1016/j.biocon.2008.07.004

Source

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