Kokeshi nobu - Kokeshi nobu

An evergreen fern of the Hymenophyllum family. The rhizomes are thin and tangled, growing long and dense with leaves 3-5 cm long. The leaf blades are thin, membranous, oblong, dark green, and pinnately lobed 2-3 times. The pinnae branch out from the central axis at acute angles of 30-45 degrees. The central axis and the pinnae have wings. The lobes are linear, 1.5-2 mm wide, and have a group of sporangia at the end, which are wrapped in a broad, ovate, deeply lobed envelope with two petals. It grows on rocks or tree trunks in humid forests in the subalpine zone. Hymenophyllum barbatum is slightly larger than Hymenophyllum barbatum, with leaves 3-10 cm long and sharp sawtooth edges on the lobes. It grows on rocks and tree trunks, as well as in dry areas in forests of low mountains in various places. The Kiyosumi Moss Ficus oligosorum grows on tree trunks in forests in warm regions west of the Kanto region, and has small leaves 2-4 cm long with hairs growing on the veins on the underside, making it distinguishable from other Moss Ficus genus leaves. The narrow-leaved Moss Ficus oligosorum is large, 10-15 cm long, with pinnae branching out from the central axis at obtuse angles (45-70 degrees) and thin lobes 0.5 mm wide. It is found in warm regions west of the Kanto region.

[Makoto Nishida]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

コケシノブ科の常緑性シダ。根茎は細く、もつれ合って長く伸び、長さ3～5センチメートルの葉を密生する。葉身は薄い膜質の長楕円(ちょうだえん)形で暗緑色、2～3回羽状に分裂する。羽片は中軸から30度ないし45度の鋭角に分出する。中軸、羽軸には翼がある。裂片は線形で幅1.5～2ミリメートル、末端に胞子嚢(ほうしのう)群が生じ、2弁に深裂した広卵形の包膜で包まれる。亜高山帯の多湿の森林の岩石上、または樹幹に着生する。コウヤコケシノブHymenophyllum barbatumはコケシノブよりやや大きく、葉は長さ3～10センチメートル、裂片の縁には鋭い鋸歯(きょし)がある。岩上や樹幹に着生するほか、各地の低山の森中の乾いた所にも生える。キヨスミコケシノブM. oligosorumは関東以西の暖地の森林の樹幹に着生し、葉は小形で長さ2～4センチメートル、裏面の脈上に毛が生えているので他のコケシノブ属と区別できる。ホソバコケシノブM. polyanthosは大形で長さ10～15センチメートル、羽片は中軸から鈍角（45～70度）に分出し、裂片は細く幅0.5ミリメートル。関東以西の暖地に分布。

［西田　誠］

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