Rise and fall of exotic species: Dr. Makino and Juncus tenuis Willd. around Yokohama Zoorasia

Tomitaro Makino 牧野富太郎 is regarded as the Father of Japanese botany. During his long life of 1862-1957, he named more than 2500 plants among which were about 600 newly discovered species. He also went all over Japan when amateur plant lovers needed his professional advice, from identification to “how-to-organize plant searching volunteer groups.” He was a scholar, and so fought usual “academic politics” many times. He was both difficult and friendly. After his death people’s admiration for him has not waned. He’s a kind of hero in Japan. His fame remains in our community as well. He helped establish plant lovers’ associations in Kanagawa Prefecture. Do you remember uber publication, Flora of Kanagawa, by the Flora Kanagawa Association (my post on November 5, 2021)? That Association is receiving BIG help from Flora Yokohama Association that was first established in Yokohama in 1909 with the help of Dr. Makino. It was the first for such association in Japan. Especially in his early days as a scholar, Dr. Makino researched plants in Yokohama, and found many exotic species that were brought in probably from the vessels of foreign routes calling at the port of Yokohama. One of such species was Juncus tenuis Willd. 

When Dr. Makino found Juncus tenuis Willd. in a forest near the present-day Yokohama Zoorasia, he thought Gotcha, and named the grass “Shirane-i” in Japanese. You see? The address for Zoorasia is (Kami-) Shirane township. Alas, he failed in the race of putting Japanese name of this weed. Jinzoh Matsumura 松村任三, Makino’s boss for Tokyo University and the first director for Koishikawa Botanical Gardens, anointed the grass “Kusai-i.” “Kusai-i” became the official Japanese name of Juncus tenuis Willd. Makino’s “Shirane-i” sometimes appears in an encyclopedia after “Kusai-i” entry, as “aka.” Dr. Makino, it seems to me, remembered the episode well. In 1947, he wrote a small essay in his magazine “Makino-shokubutsu Kon-kon-roku 牧野植物混混録” (; oh, dear …, how to translate this title … it’s like Makino’s Everything Plants Magazine …?). In it, he wrote when he discovered it in Yokohama, around 1900, it was fairly rare species, and so “I should be deserved for the honor of naming right!!!” is his opinion between the lines of essay. By 1947 the plant became ubiquitous all over Japan, he said. Then, more than 70 years later, what is happening for Juncus tenuis Willd. in the forests Dr. Makino found it and thought he was the first in Japan to recognize it? I did a little research.

The Juncus family loves to thrive near and/or in small streams. What’s happening for such environment around Zoorasia? A-hem, the majority for the flow of water near the Zoo is modified as culverts, or landscaped artificial flows accompanying underwater pipe acting as sewage. So far, I have not found a place where any weed of Juncus family thrives naturally near Zoorasia. The pervasive presence of Juncus tenuis Willd. Makino mentioned does not exist any more in the 21st century ... Makino is famous for his superb botanical paintings and his supreme making of specimen. I asked 3 museums that have specimen made by Dr. Makinos if they have Juncus tenuis. Makino Herbarium of Tokyo Metropolitan University does not have it. Nor Kochi Prefectural Makino Botanical Garden. Tokyo University has the specimen of Juncus tenuis Willd. made by Dr. Makino, but it was collected in the campus, not in Yokohama. His specimen for Juncus tenuis Willd. from the forests near Zoorasia had gone when Great Kanto Earthquake hit Kanto Region in 1923. There’s no back-up evidence of his findings of Juncus tenuis Willd. Only his murmurs about it remains.

Where is Juncus tenuis Willd.?

Heavily urbanized environment around Zoorasia, at least in terms of water management, makes the habitat drier. Instead of Juncus family, Cyperaceae family is expanding their territory. Just a casual look, I could find 3 species of Cyperaceae family in large colonies. One is tall flatsedge which is also of foreign origin, from South America to be exact. What would Dr. Makino have said for such changes for exotic species in the city of international port? I felt a bit comical Dr. Makino’s remarks about naming Juncus tenuis Willd. Exotic Juncus were everywhere in Japan once, but now only the mentioning of it by our superstar scholar remains. Alternatively, a new-comer is covering the territory they’ve found comfortable. Will they last, or go the same way Juncus did? There always is a rise and fall …

Cyperus microiria

Cyperus flavidus Retz.

Cyperus eragrostis

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

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