Grass button - Grass button

A perennial plant of the Ranunculaceae family (APG classification: Ranunculaceae). Although it is a member of the Clematis genus, which is a vine-like plant, the stem is erect and 1 meter tall, with woody lower parts. The leaves are large, trifoliate, and opposite, with ovate leaflets and thick, coarsely toothed leaves. The flowers are pale purple, about 2 cm long, and bloom in August to October in large panicles, many of which are downward-facing, thin, bell-shaped, with four sepals with recurved tips. All flowers have stamens and pistils, but are functionally differentiated into male and female flowers. The fruit is an achene, with a long, feathery style remaining. It grows on forest edges and grasslands, and is distributed throughout Honshu. A variant of the plant, Tsukushikusabotan, is distributed in Shikoku and Kyushu, and often grows on limestone ground. In the Hokuriku region, there is another species, C. satomiana Kadota, which has blue-purple, broad, bell-shaped flowers.

[Yuichi Kadota March 18, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

キンポウゲ科（APG分類：キンポウゲ科）の多年草。つる植物が多いセンニンソウ属の一つであるが、茎は直立し高さ1メートル、下部は木化する。葉は対生し、大形の1回3出複葉、小葉は卵形で厚く粗い鋸歯(きょし)がある。花は淡紫色、長さ約2センチメートル、8～10月、大きな円錐(えんすい)花序に多数が下向きにつき、細い鐘形で、4枚の萼片(がくへん)の先端は反り返る。すべての花に雄しべと雌しべがあるが、機能的に雄花と雌花とに分化している。果実は痩果(そうか)で、羽毛状の長い花柱が残る。林縁や草原に生え、本州に分布する。四国、九州には変種ツクシクサボタンが分布し、石灰岩地に生えることが多い。北陸地方には花が青紫色で幅広い鐘形の別種ホクリククサボタンC. satomiana Kadotaがある。

［門田裕一　2020年3月18日］

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