Gymnocarpium

...A delicate fern of the Gymnocarpaceae family that grows under forests in Honshu north of the Chubu region and Hokkaido. It is widely distributed in the temperate zone of the Northern Hemisphere. The rhizome runs long and slender underground, and the leaves grow sparsely. The rhizome and petiole have scales. The leaves are 20-50 cm long, and the petiole is longer and thinner than the blade. The lowest pinna is significantly large, and the blade is pentagonal, pinnately lobed 2-3 times, and tilted to the petiole. The leaf is soft. The rachis is articulated to the mid-rachis. The sporangia are circular, located near the margins of the leaves, and lack an intumescent membrane. Six species of Gymnocarpium are known in the temperate zone of the Northern Hemisphere, and belong to the Gymnocarpaceae family. ...

*Some of the terminology that mentions "Gymnocarpium" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…中部地方以北の本州と北海道の林下に生える繊細なメシダ科のシダ。北半球の温帯に広く分布する。根茎は細長く地中を横走し，葉をまばらにつける。根茎と葉柄には鱗片がつく。葉は全長20～50cm，葉柄は葉身より長くて細い。最下羽片は著しく大きく，葉身は五角形になり，2～3回羽状全裂，葉柄に対して傾いてつく。葉質はやわらかい。羽軸は中軸に関節する。胞子囊群は葉の辺縁よりにつき円形，包膜はない。　ウサギシダ属Gymnocarpiumは北半球の温帯に6種知られ，メシダ科に属する。…

※「Gymnocarpium」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報