Michiyanagi - Michiyanagi

An annual plant of the Polygonaceae family (APG classification: Polygonaceae). It is glabrous and green, and does not turn black even when dry. The stem branches at the base, rises, is 10-40 cm tall, has many vertical stripes, and swollen nodes. The leaves are short-stalked, alternate, oblong, 2-4 cm long, rounded at the tip, glabrous along with the stem, and have a prominent mid-vein on the underside. The leaf sheaths are membranous, irregularly lobed, and have fine veins. From July to September, several green florets grow in bunches in the leaf axils. There are five perianth pieces, with white or pink edges. The achene is triangular, finely wrinkled, and surrounded by the perianth pieces. It is a common roadside weed that is widely distributed throughout Japan and the temperate and subtropical regions of the Northern Hemisphere. Its name comes from the fact that its leaves resemble those of a willow and it grows on paths and in gardens, hence its other name Niwayanagi (garden willow). The young leaves are edible. The whole plant contains silicic acid, and when dried it is used for jaundice, stomach pain, and as an anti-worm treatment.

[Junko Kobayashi December 11, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

タデ科（APG分類：タデ科）の一年草。全体無毛で緑色、乾いても黒変しない。茎は基部で分枝して立ち上がり、高さ10～40センチメートル、縦条が多く節は膨れる。葉は短柄があって互生し、長楕円(ちょうだえん)形で長さ2～4センチメートル、先は丸みを帯び、茎とともに無毛で、裏面は中央脈が浮き出る。葉鞘(ようしょう)は膜質で不規則に細裂し、細脈がある。7～9月、葉腋(ようえき)に緑色の小花を数個束生する。花被片(かひへん)は5枚で、縁(へり)は白色または桃色を帯びる。痩果(そうか)は三稜(りょう)形で細かい皺(しわ)があり、花被片に包まれる。道端に普通に生える雑草で、日本全土、および北半球の温帯、亜熱帯に広く分布する。名は、葉形がヤナギに似て、道や庭に生えることにより、別名ニワヤナギ（庭柳）ともいう。若葉は食用となる。また全草にケイ酸を含み、乾燥して黄疸(おうだん)、腹痛、虫下しなどに用いる。

［小林純子　2020年12月11日］

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