Barbarea vulgaris (春咲山芥子, ハルザキヤマガラシ)

Another weed! Yay! I keyed this one out to the genus Barbarea in Ohwi's Flora of Japan, and it only listed one species, namely Barbarea orthoceras Ledeb., which is called American yellowrocket in English (cool name, right?!), but it's also native to Japan and East Asia. There were some inconsistencies with the leaf shape, among other things, so I looked up some photos of it and decided it was close to the plants I was examining, but not quite right. I then came across some photos of Barbarea vulgaris R.Br., called garden yellowrocket, which matched the plant I had found much better. Sure enough, a search revealed that garden yellowrocket is established in Japan, from Hokkaido to Kyushu.

The plant is a true Eurasian: it's native from Ireland to at least the Urals and India. It may be native t0 western China (eastern Turkistan, a.k.a. Xinjiang), and some sources suggest perhaps all the way to Korea, but I can't find anything completely convincing of either claim. At any rate the plant is very widely distributed in Eurasia and it's biogeography has been giving me a headache, so I'll just assume that it's only native to Europe and Western Asia. It's quite certainly introduced in Japan anyways.

I found this plant in an attempt to find slightly more "natural" plant habitat. It was growing right on the banks of the Toné River (利根川), but the habitat there wasn't a whole lot better than the weedy lots I had been searching up to that point. There were trees and bamboo, but only one species of each. The trees were instantly recognisable: black locust (Robinia pseudoacacia) introduced from the US. It's quite a weedy tree where I'm from as well, but it had really formed a fairly extensive monoculture on the slopes along this river, at least at the canopy level. The bamboo I would have to look at more closely, but it was short and so densely packed that nothing would survive beneath it. The only natives I found were some willows growing in the water.


Anyways, garden yellowrocket is common along ditches, river banks, damp grasslands, roadsides, fields, and in other nondescript disturbed sites. It has a similar floral arrangement to it's cousins, such as the two members of the cabbage family that I've posted on previously. As for seeds and capsules, the plant I photographed hadn't produced any yet, so check the links for photos of those. The leaves seem to be one of the most distinctive features. The upper leaves are ovate, meaning "egg-shaped", to suborbicular, which means "nearly circular", and the margins are usually sinuate (i.e. wavy; see my photo below) to very coarsely dentate (i.e. toothed). The basal leaves are less special; they are lyrate (i.e. lyre-shaped, but more specifically meaning "having a large terminal lobe and smaller rounded lobes toward its base") and form a basal rosette, but on the plant I found they were chewed down to almost nothing. See some of the links for photos of these too.

The rather long Japanese name of this plant is 春咲山芥子 (ハルザキヤマガラシ; haruzaki-yamagarashi), which means "spring flowering mountain mustard". It's a cousin of the plants whose seeds are used to make mustard (all in the cabbage family, or Brassicaceae), namely Brassica nigra, Brassica juncea, and Sinapis hirta. As an aside, the genus Brassica easily includes more important food plants than any other: cabbage, broccoli, Brussels sprouts, rapeseed, canola, cauliflower, kale, turnip, kohlrabi, collard greens, Chinese cabbage, rapini, rutabaga (or Swede turnip), kai-lan (or Chinese broccoli) and, of course, mustard. Our plant of interest is also called 西洋山芥子 (セイヨウヤマガラシ; "seiyou-yamagarashi"), which means "Western countries mountain mustard". Both names serve to differentiate it from the native Barbarea orthoceras, which is just called 山芥子 (ヤマガラシ; "yamagarashi"), or "mountain mustard".

The English name, garden yellowrocket, has nothing to do with the things they shoot in to space, but rather is in reference to it being a yellow-flowered plant quite similar to the true rocket, Eruca sativa (a quick examination of the generic name Eruca might clue you in to the fact that the plant name "rocket" is derived from it). Most English speakers would probably know rocket as arugula, the Italian name for the same plant derived from the same root that was introduced in order to make this age-old leaf vegetable seem more exotic.

Links:
Flora of China Treatment
Random Japanese page
MissouriPlants.com entry
Ultraviolet photos of the flowers (what insects see)

Centaurea cyanus (矢車菊, ヤグルマギク)

Okay, so this is quickly becoming a compendium of global weeds, but alas, I haven't had a chance to explore any relatively undisturbed areas yet. This next one is a native of southern Europe and is widely cultivated & established elsewhere. As an aside, the plant is protected as an endangered plant as a part of the UK's rather different environmental protection policy. I usually don't think of exotic species as worthy of government protection, but apparently somebody must; see this link.



Anyways, I found it growing within a metre of a previously mentioned 1,500+ year old Kofun (古墳), or megalithic keyhole-shaped burial mound, which is within 50 metres or so of my apartment. They are quite common in the area, and as such this particular one only has a little sign in front of it in Japanese saying (presumably) what it is, but it's surrounded by houses and ugly apartment buildings and it sort of blends in with the landscape when you're not viewing it from above. I walked past it several times without even realising it was anything more than a somewhat strangely designed public park. Here is a GoogleMaps aerial view of the mound for those that are curious about the shape:


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The English name for this plant is blue or common cornflower, while the scientific name is Centaurea cyanus L.. "Cyanus" means "blue" while the genus name derives from the Ancient Greek "kentaurieon", an ancient plant name associated with Chiron, a centaur famous for his knowledge of medicinal plants. The plant is an important symbol for various things in European culture, perhaps most notably as the national flower of Estonia (see the Wikipedia article for more on its symbolism). Aside from its use as a cultivated plant, it also has a number of medicinal applications, it was once used for a blue pigment, and it's apparently used in Twining's Lady Grey tea blend. The name is derived from the fact that it is a weed of corn fields (corn fields in the British sense of corn, of course).

The Japanese name is 矢車菊 (ヤグルマギク), which is read as "yaguruma giku". The name translates as "arrow wheel chrysanthemum". An arrow wheel is a decorative wind mill placed on the top of a pole supporting carp-shaped streamers known as "koi no bori" (鯉幟). They are flown during what used to be a holiday on the lunar calendar called "tango no sekku" (端午の節句), which celebrated the start of the rainy season, but has since been adapted to the Gregorian calendar under the new name "kodomo no hi" (子供の日), which means "children's day". Celebrated on May 5th, Children's Day is the combination of Boy's Day and Girl's Day, which used to be celebrated seperately on 5th and 3rd of May respectively. In typical sexist fashion, they made sure to make Girl's Day a part of Boy's Day and not vice versa (the change happened in 1948). Anyways, Children's Day celebrates children's happiness and personalities, and the carp streamers topped with arrow wheels somehow express the wish for families' boys to grow up strong. I personally don't see the connection between pond scum-eating fish and the hope for boys to turn out well, but it wouldn't be the first time that something Japanese made no sense. At any rate, the arrow wheel looks quite similar to the flower that is supposedly the topic of this post (see the link to the Gunma Botanical Garden entry for a photo comparison).

Unfortunately, the current generic name "Centaurea" might not stick for this plant. Recent genetic work has shown that the genus is polyphyletic, meaning the species within it do not form a single natural group. Linnaeus, the author of this particular species as well as the genus, rather inconveniently chose Centaurea centaurium as the type species for the genus, and as that particular species is African and does not group with most of the 500 or so other species currently called Centaurea, either the vast majorit will come under new generic names, or the generic name will be conserved by changing the type specimen and the aforementioed African species as well as other oddballs will get new generic names. The plants in the genus are, generally speaking, distinguished from other members of the aster family (Asteraceae or Compositae) by their often deeply lobed leaves, their spiny or comb-like phyllaries (i.e. the leaf-like bracts below the flowers or on the buds; see the last photo), as well as floral features such as typically sterile outer florets, branched styles and tailed anther bases. This particular cornflower is distinguished from its close relatives by its non-spiny phyllaries with very fine appendages, its annual habit (check the roots; if they're very robust it's not an annual), and it's short pappi (the bristley things on the seeds). Two color forms exist, blue & pink, as well as some intermediates (see photos).


Some links:
Flora of North America treatment
English Wikipedia entry
MissouriPlants.com entry
Gunma Botanical Garden entry (Japanese)

Tristagma uniflorum (花韮, ハナニラ)

This native of Argentina & Uruguay is not mentioned in Ohwi's flora, but it's listed by the Ministry of the Environment as one of the 1,556 alien plants recognised as established in Japan. It's also very popular in gardens. I've seen it carpeting people's front gardens and then extending out onto the curb side and then even down the road a ways. It's apparently also naturalised in parts of the southeastern United States from Texas to Virginia, as well out west in California and Oregon, and even in Europe in France and the UK.

The English name is "spring starflower", for obvious reasons. The Japanese name is 花韮, (ハナニラ) which is read as "hananira" and means "flower garlic-chives". The second character alone, read just as "nira", is the word for Allium tuberosum (garlic-chives), which is an onion relative grown for its somewhat chive-like leaves. It's rare in western kitchens, but is ubiquitous in Asia. The spring star flower has similar looking and smelling leaves, hence the Japanese name.

In fact, under the APG II (Angiosperm Phylogeny Group) taxonomic system, the spring starflower has been placed in Alliaceae, the onion family, which also includes garlic-chives as well as any other chive. The move is part of a huge fracturing of the once enormous Liliaceae (lily family) into many smaller families, largely on the basis of new molecular (i.e. DNA) evidence. The scientific name is currently a matter of contention. It's often treated as Ipheion uniflorum (Lindl.) Raf., but in 1963 Hamilton P. Traub proposed that the entire genus Ipheion be collapsed into Tristagma, a closely related genus, yielding the name Tristagma uniflorum (Lindl.) Traub. Only more research will provide a more difinitive classification.


There's not too much more to say, and it's not very important culturally in Japan as it's a recent introduction. Plants have only basal leaves and a single flower on a scape that's usually less than 20 cm, both of which grow from a membranous subterranean bulb. The stamens are conspicuously unequal (3 long, 3 short), which separates this plant from most others in the onion family. The ones that I saw where nearly snow white, but they can be found flushed with a blue-violet.

Some links as usual:
Jepson Manual treatment (Flora of California)
Wikipedia entry (English)
Wikipedia entry (Japanese)

Capsella bursa-pastoris（薺, ナズナ）

This plant makes the last weed pale in comparison, but only really in so far as weediness is concerned. This is, according to the Flora of China, the second most common weed on earth (I wonder what the first is; maybe the dandelion...). The same work also says that it's native to Europe and southwest Asia, but Ohwi's Flora of Japan makes no reference to it being introduced and he seems to disclude most non-native plants. I've personally seen it on 4 continents now: North America, South America, Europe & Asia, so the 2nd most common weed thing doesn't seem too far off. It grows virtually everywhere where there are people or open fields in the world's temperate zones. In Japan, Ohwi says it is "very common" on the 4 main islands in fields and streetsides in lowland areas.


The plant is called "shepherd's purse" in English because of its purse-like capsules (the capsules are called "silicles" in cabbage family-speak). In German, where I collected it for a class I was taking there, it's called "Hirtentasche", which means "heart purse", which I think is more obvious since I can't say I've ever seen a shepherd's purse. It has it's own kanji, 薺 (ナズナ), which is read as "nazuna". In simplified Chinese that character was reduced to 荠, which is "qi" in Mandarin, and it has the same meaning as the Japanese. In Traditional Chinese the character is the same as the Japanese one. However, the original meaning of the character was apparently "water chestnut", which in Japanese is クログワイ ("kuroguwai") and doesn't seem to be associated with a kanji. Meanwhile, the modern Chinese name for the water chestnut became 荸薺 (traditional) or 荸荠 (simplified). Notice that the second character in both compounds is the one used for shepherd's purse in modern Chinese. So my guess is that by the time the character was exported from China to Japan, shepherd's purse had been introduced to east Asia and the Chinese were denoting it using their old character for water chestnut unbeknown to the Japanese.

Anyways, I shouldn't waste too much time on this plant. It's really easy to identify because of its heart-shaped capsules. The leaves form a basal rosette that looks superficially similar to a dandelion rosette, but usually the plants occur en masse and are so sprawled out out dumping their seeds everywhere that you tend not to notice the leaves. The flowers are of the typical cabbage family (Brassicaceae) variety, which is to say they have 4 sepals, 4 clawed petals, 6 stamens and a bilocular ovary. The seeds are tiny and oblong.

Although Capsella bursa-pastoris (L.) Medik is superficially rather boring, it does have some interesting features. Coolest among them is that it has carnivorous seeds. The seeds secrete a mucilage when exposed to water, which gives off chemical signals that attract various small invertebrates. The inverts then become stuck to the seeds, which also secrete toxins to kill them and enzymes to digest them. What's the point of this? Fresh fertiliser for every seed! Another cool tidbit would be that all parts are edible and medicinal. The young leaves are apparently pretty good, but I haven't tried yet, while the older ones are said to be quite peppery. Medicinally, it's used by herbalists across the world for things such as eye diseases, dysentery and bloody noses.

Here are some links:
Flora of China treatment
Flora of Pakistan treatment
Flora of China illustration
MissouriPlants.com account
Barber (1978) "Capsella bursa-pastoris seeds: are they carnivorous?" (.pdf)

Orychophragmus violaceus (大紫羅欄花, オオアラセイトウ)

This one is truly a weed, but a very pretty one for sure. It's found in all kinds of ruderal places, from street sides to grassy fields. The plant is introduced from China, and the Japanese don't seem to know what to call it. It has at least 5 common names here. I've chosen to use the longest of them, since it seems to be used most often: 大紫羅欄花 (オオアラセイトウ), which is read "ooaraseitou". The name means something like "great-column-of-purple-silk flower". Not even Japanese would be able to write that name in Kanji (i.e. the Chinese characters used to write Japanese). Other names include 紫花菜 (ムラサキハナナ, "murasakihanana"), meaning "purple-flower rape" (rape as in rapeseed of course), 紫金草 (シキンソウ, "shikinsou"), meaning "purple-gold plant" and 諸葛菜 (ショカツサイ, "shokatsusai"), which is apparently the original Chinese name. It's also called 花大根（ハナダイコン, "hanadaikon"), which means "flower daikon" (a daikon being a huge radish for those of you not up on your Japanese veggies), but only because it resembles the related Hesperis matronalis, which is apparently the true hanadaikon, and it is also introduced. Oh, and it doesn't have a common name in English


So if you haven't guessed after all the names referencing radishes and rapeseed, the plant is in the radish and rapeseed family, more often called the cabbage family, or the crucifers (Brassicaceae). Orychophragmus violaceus (L.) O. E. Schulz is native to China and Korea, but was introduced to Japan some time ago. One source I looked at says that the plant was introduced sometime during the Edo period (江戸時代), which ran from 1603 to 1868, apparently as an ornamental. As is often the case, it escaped from cultivation and spread all over. The flora of China says that it is common in "roadsides, gardens, forests, fields, thickets, valleys, hillsides, and sunny slopes", which seems more or less accurate for Japan too. It's one of two species in its genus, with the other, O. limprichtianus, being endemic to China.

The plants are relatively big, averaging a half a metre tall, though some grow up to just shy of a metre. One of the reasons that they are so successful may stem from the fact that each ovary has 40 to 70 ovules, and given that each plant is loaded with flowers, individuals are producing seeds in the thousands. Not that you would see the other species here, but the great-column-of-purple-silk flower (I don't think that name will catch on abroad...) has auriculate leaves, meaning that they have ear-like projections that clasp the stem and stick out on the opposite side, while the other species does not. Our topical species also has petals with very distinct claws (i.e. the stalk-like part of the petal), which the other species lacks. The plant didn't really look like a crucifer to me at first, probably because I don't recall seeing many violet-flowered crucifers before, but it's got all the typical features, from the flowers to the siliques (i.e. the fruit common among crucifers), although the shape of the anthers seems perhaps a bit odd for the family. Oh, and the flower colour ranges from a light blue to a fairly deep purple, even within the same stand. A nice weed to have around!

Here are some useful links with more information
Flora of China entry
Flora of China illustration
Account from the "Japanese Plant Watcher's Page"

Viola mandschurica (菫、スミレ）

I've only been in Japan for about a month, and in Maebashi, where I will be living for the next year, for under 2 weeks. So far most of the plants that I have found have been introduced, mostly from China, but I wanted to start the blog off with a native plant. To my pleasant surprise, I found a nice native violet while I was on my way to photograph another non-native plant which I'll cover later. I found it in quite an idyllic spot too. Gunma prefecture is quite famous for its ancient burial mounds, and those from the Kofun Period (古墳時代), which ran from 250-538 AD, are shaped like giant keyholes (in fact there is one just 50 meters from my apartment!). I found this plant on a burial mound, but it wasn't a Kofun one as it was just a nondescript mound, and it had modern graves on it, so it was either old and reused or else relatively recent, though it did have trees that were at least 60 years old on it.

The Manchurian violet (Viola mandschurica W. Becker), or 菫 (read as "sumiré"), is probably the most common violet species in the country, at least from what I can gather. Indeed, the name "sumiré" is a general term for violets, but this species is so common that no further descriptive adjective is added to the name: it is "the violet" in Japan, as it were. The flora that I'm using, The Flora of Japan (in English) by Jisaburō Ohwi, states that it is "very common" and is found on all the major islands of Japan (not including the Ryukyu Islands, as they weren't a part of Japan when the flora was published in 1965). I've seen it growing in the cracks of pavement and in little spaces on walls. The ones I found photographed were practically carpeting the ground under a number of cherry trees, but with good light coming in from the south. In fact, on the north side of the hill I didn't see any, so shade is proabaly a strongly limiting factor in their habitat preference. The flora says they're typical of "grassy places and fields in lowlands and hills".

It's not only in Japan that this plant is common. In fact, it's quite widespread, and is found in the Russian Far East, Korea, Taiwan, and throughout eastern China down to Fujian and all the way up to Inner Mongolia and Manchuria, whence it's English and scientific names.

Anyways, it's distinguished by its winged, broad, short leaf stalks ending in a deltoid-lanceolate (i.e. triangular-lance-shaped), somewhat thick leaf, as well as by its dark-purple flowers, though occasionally white ones with purple striations turn up. You can see the winged petioles as well as the leaf shape in the first photo. The lateral petals are usually bearded on the inside, but they are sometimes glabrous (i.e. hairless), such as the ones I photographed. Also notice the 5-8 mm sepals on the unopened flower. The roots are orange brown, which differentiates this species from some others with white roots. For a detailed line drawing, please click on the Flora of China illustration in the links section at the bottom of this posting.

Apparently the plant is grown in the West by violet enthusiasts, particularly a cultivar called 'Fuji Dawn' that has very beautifully variegated leaves. Here is a link to a photo of the cultivar.

Here are some links to more information:
Flora of China Treatment
Flora of China Illustration
Japanese Wikipedia Entry

Raison d'être

After lots of searching on the net, I've been unable to find any comprehensive information (at least in a language that I understand) about plants in Japan, let alone in my specific area. I've spent the last few years building up my credentials in botany with the aim of doing a PhD in systematic botany, but for some reason I've decided to teach English in Japan for a year. I've been interested in Japanese culture and language since I was quite young.

But being here is also a great oppurtunity to learn a new flora that is, on the whole, quite closely related to the flora of eastern North America where I am from (originally Washington, D.C., more recently Rappahannock County, Virginia). I am especially lucky (others would say unlucky) because I am out in a relatively rural area very close to some big, heavily wooded volcanic mountains, i.e. there should be lots of plants around. To be more specific, I am living in Sannō town (山王町) which is within the boundaries of Maebashi City (前橋市), though the wheat fields around my aparment aren't very indicitive of a city.

The aims of this blog are the following:

1) Attempt to create a comprehensive database of the plants in Gunma Prefecture (群馬県), Japan, as well as post a bit on other aspects of local biology

2) Blab generally about plants and biology

3) Talk about my experiences in Japan a little bit

できるだけがんばってやってみます! (I'll try my best!)