Screech - Screech

A perennial plant of the Polygonaceae family (APG classification: Polygonaceae). The roots are thick and yellow. The stems are erect, thick and glabrous, and 0.6-1 m tall. The basal leaves have long stalks, are ovate-narrow oblong, 10-25 cm long, have wavy edges, and are hairless on both sides, but some have stiff hairs along the veins on the underside. In June and July, bisexual flowers grow at each node of the panicle, and each whorl contains small leaves. There are six tepals, the outer three of which are narrow, and they unfold when the fruit is formed. The inner three become larger after the flowering season, becoming broadly ovate and wing-like, with teeth on the edges, and a narrow ovate, knob-like protrusion at the base of the midvein. The achene is triangular, 2.5 mm long, brown and shiny. Distributed in Japan, the Korean peninsula, and China. The young shoots are edible, and the roots contain anthraquinones and are used as an external medicine for skin diseases.

The Rumex genus is found in abundance in the Northern Hemisphere and has about 200 species, 14 of which are found in Japan. Rumex rhamnoides and Rumex rhamnoides are representative, and there are also many naturalized species such as Rumex punctata and Rumex crispus.

[Junko Kobayashi December 11, 2020]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

タデ科（APG分類：タデ科）の多年草。根は太く黄色い。茎は直立し無毛で太く、高さ0.6～1メートル。根出葉は長い柄があり、卵状狭長楕円(だえん)形で長さ10～25センチメートル、縁(へり)が波打ち、両面とも毛がないが、裏面の葉脈沿いに硬い毛があるものもある。6～7月、円錐(えんすい)花穂の各節に両性花が輪生し、各輪に小形の葉が混じる。花被片(かひへん)は6枚で外側の3枚は狭く、果時に展開する。内側の3枚は花期後に大きくなり、広卵形の翼状となり縁に歯牙(しが)があり、中脈の基部には狭卵形の瘤(こぶ)状の突起がある。痩果(そうか)は三稜(さんりょう)形で長さ2.5ミリメートル、褐色で光沢がある。日本、朝鮮半島、中国に分布。若芽は食用となり、根はアントラキノン類を含み、皮膚病の外用薬とする。

　ギシギシ属は北半球に多くみられ、約200種あり、日本には14種分布する。ノダイオウやマダイオウはその代表的なものであり、アレチギシギシやナガバギシギシなどの帰化種も多い。

［小林純子　2020年12月11日］

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