Resilient: Asarum nipponicum F.Maek. var. nipponicum in Kanagawa’s forest カンアオイ

 

Do you know Asarum nipponicum F.Maek. var. nipponicum? It’s Japanese endemic plant, and secretly popular among aficionados of such things. Actually the family crest for Tokugawa Shogunate was designed from Asarum caulescens, aka Aoi, a relative of Asarum nipponicum. Asarum caulescens is also used as a motif for the crest for Kamo Shrines 賀茂神社 in Kyoto, and for the name of Aoi Festival on every May 15th, one of the three biggest festivals of Kyoto. Maybe, this strange plant has something to do with unconscious aesthetics for Japanese culture ... oh, quite unfortunately, COVID-19 cancelled this year‘s Aoi Festival again, 3 consecutive times ... In some sense, it‘s very “main stream” plant. If you know them, you can find them even in city parks of Megalopolis Tokyo. I know at least 3 city parks having them. I won’t tell you where, though, to protect them. 😉 There is one caveat for this plant to live in a city park: the place for Asarum nipponicum and its relatives must be undisturbed by human intervention for a very long time. When we find them in a park where lots of transplanted garden species are competing for the eyes of visitors, that particular 50cm * 50cm space happens to be unruffled. There is a reason why it must be so: their lifestyle.

Young Asarum caulescens Maxim.

The crest for Tokugawa Shogunate

The crest for Lower Kamo-shrine

The crest for Upper Kamo-shrine

Let‘s start from the anatomy of Asarum nipponicum. They have only a short stem that crawls underground. Their leaves and flowers sprout from it. It looks like they come out directly from the floor. Flowers have 3 calyxes that look like petals. The calyxes construct a jar structure which contains only stamen and pistil without petal. The color of calyx is very dark purple or purple brown which can easily fool our eyes in dark forest floor. Moreover, the flowers often hide behind the leaves. We simply wonder how they procreate in such extreme understatement of their sex appeal. Some say they smell nice. I never find so. One theory says they emit chemical that would attract crawling insects such as ants. Well, OK. They can bear seeds, then. The next question is how they sprout. Their seeds have elaiosome, just like violets, which is tasty for ants et al. The bugs can come to bite elaiosome and carry seeds of Asarum. The seeds of Asarum nipponicum may find a new territory … If they cannot find such a kind driver to move around, their seeds will sprout very near their parents. Since the plant is almost pasted on the forest floor, their seeds cannot go much far. Prof. Fumio Maekawa (1908-1984) 前川文夫 of Keio University estimated for Asarum nipponicum to move 1km, it will take 10 thousand years. Phew. It means, when we find a bunch of Asarum nipponicum in a park, they must have procreated on that spot and their seeds are sprouting right next to the ancestors for a very long time. Corollary: the place has not been disturbed for quite some time. Got it?

Asarum pseudosavatieri F.Maek.;
Heterotropa savatieri Franch. subsp.
 pseudosavatieri (F.Maek.) T.Sugaw.

A flower of Asarum pseudosavatieri F.Maek.

Conversely, when the ground is upset, the standard lifestyle of Asarum nipponicum is disrupted. That might be a reason several sub-species of Asarum nipponicum is in the danger of extinction. In Kanagawa prefecture, there are 7 kinds of Asarum nipponicum identified. So far, I’ve seen 4 of them in Tanzawa mountains 丹沢. Asarum caulescens Maxim., Asarum blumei Duch.; Heterotropa blumei (Duch.) F.Maek., Asarum nipponicum F.Maek.; Heterotropa nipponica (F.Maek.) F.Maek., and Asarum pseudosavatieri F.Maek.; Heterotropa savatieri Franch. subsp. pseudosavatieri (F.Maek.) T.Sugaw. All looked pasted on a very steep scree slope of Tanzawa. I simply wonder how they sustain their species in such a fragile soil ...

Asarum blumei Duch.; Heterotropa blumei (Duch.) F.Maek

Asarum nipponicum F.Maek.;
Heterotropa nipponica (F.Maek.) F.Maek.

Then I noticed. In Tanzawa, they often spread vertically. One Asarum nipponicum is over there high on the slope, then a new Asarum is sprouting on the side of trekking road. From our foot they continue to the down-slope. I guess when water run down or ground collapse over the steep slope, the seeds of Asarum hitch the flow and go downhill from their parents place. Their spread may show the way the earth and water move … It is impressive sight. These tiny leaves (and flowers) are using the characteristics of the environment they find to continue their species. They are so resilient despite of their physical limitation. That’s something.

Spring this year in Tanzawa.
Up there of the slope there are lots of
  Asarum pseudosavatieri F.Maek.

T

Then, Asarum pseudosavatieri casually come down
 to our foot along the trekking road of Tanzawa.

They‘re down there.

The existence of 7 kinds of Asarum nipponicum in Kanagawa Prefecture is endorsed by Flora-Kanagawa Association 神奈川県植物誌調査会. This group of scholars and citizen volunteers maintains continuous field research to record the species observed in the prefecture. They publish Flora of Kanagawa roughly once in 10 years, reporting the result of their study. The latest version is in 2018 神奈川県植物誌2018. In pp.222-227 of 2018 version, they discuss Asarum nipponicum in Kanagawa Prefecture. Their activity and publication are authoritative in Japanese botany world. Flora of Kanagawa is often cited as a sort of benchmark for flora in the other prefectures. If you’re interested in the topic, you can download the entire 2018 version from here. Mr. Teruo Katsuyama 勝山輝男 I introduced you in my posts (here and here) for Hakone Sengokubara 箱根仙石原 was the leader for creating Association in 1979. Their idea was revolutionary establishing the system of collaboration between the academia and citizen volunteer researchers. Mr. Katsuyama is a superstar in Kanagawa Prefecture.

It’s two shots of Asarum pseudosavatieri F.Maek.
 and Asarum caulescens Maxim.

Speaking revolutionary movement for protecting greenery in Japan, I‘ve got an enquiry from Altamont about the first national trust approach in Japan by Kamakura Trust 鎌倉風致保存会 for Oyatsu 御谷. Kamakura Trust was registered as juridical foundation in December 1964. After that, the Trust became the driving force to establish the Ancient Capitals Preservation Law 古都保存法 of 1966. They then purchased the land behind Tsurugaoka Hachiman Shrine 鶴岡八幡宮 in June 1966. About the story of the movmenet, it would be much to do with Jiro Osaragi (1897-1973) 大佛次郎, a writer who spent whole his life in Yokohama and Kamakura. He was a very popular writer and had lots of powerful connections for the movement. The supporter of Kamakura Trust includes Nobel Prize winner Yasunari Kawabata 川端康成 who lived in Kamakura. For the detail, it may help to ask Kamakura Trust (link here), and Jiro Osaragi Museum (link) near the Port of Yokohama. ESD Academy that promote SDGs edu in Japan also makes a special page for their movement here. I think all these organizations have capacity to communicate in English. They may help you to know the detail.

If you find environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター

657 Nanasawa, Atsugi City, 243-0121
〒243－0121　厚木市七沢657
Phone: 046-248-0323

You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/