Meshida - Meshida

A summer-green fern of the Dryopteris family. The leaves grow to 1 meter long, are deeply pinnately lobed 3 times, soft and glabrous. The leaf blade narrows slightly at the base. The petioles are lanceolate or broadly lanceolate and sparsely covered with dark brown scales. The sporangia are rod-shaped to hook-shaped, and the insula is the same shape, with thread-like cracks at the edges. It is commonly found in the mountains of Hokkaido and rarely in northern Honshu. The Japanese name is a direct translation of A. filix-femina, which is found in Europe and the United States, but there are slight differences between this species and the fern, and the fern is sometimes called Ezomesida to distinguish it from the fern. A. melanolepis, which looks very similar to the fern, has short petioles and glossy black scales and is found in the coniferous forests of the Tohoku and Chubu regions.

[Harufumi Nishida]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

オシダ科の夏緑性シダ。葉は長さ1メートルになり、3回羽状深裂で柔らかく無毛である。葉身は基部がやや狭まる。葉柄には、披針(ひしん)形ないしは広披針形で暗褐色の鱗片(りんぺん)がまばらにつく。胞子嚢(のう)群は棒状から鉤(かぎ)形をなし、包膜も同形で、辺縁は糸状に裂ける。北海道の山地では普通にみられ、本州北部でもまれに産する。和名は欧米に分布するA. filix-feminaの直訳であるが、これと本種とはわずかな差があり、区別するときには本種をエゾメシダとよぶこともある。本種と外見はよく似るが、葉柄が短くつやのある黒色の鱗片をもつミヤマメシダA. melanolepisは、東北地方から中部地方の針葉樹林帯にみられる。

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