みやまししがしら (深山獅子頭) [Index] [Back] わが国の北海道および本州の東北地方から関東地方北部、それに北陸地方に分布しています。山地帯の落葉広葉樹林帯に生え、高さは２０〜３０センチになります。葉は胞子葉と栄養葉の二形性が著しく、胞子葉は栄養葉の２倍ほどの長さがあります。葉柄や葉軸の裏面は暗紫褐色になり、密に細点があり，触るとざらざらするのが特徴です。葉柄には線形の鱗片が密生します。  シシガシラ科ヒリュウシダ属の常緑シダ類で、学名は Blechnum castaneum。英名はありません。  "Miyama-shishigashira" (Blechnum castaneum) belongs to the Blechnaceae family. It is an evergreen fern that is distributed from Hokkaido, Tohoku district to northern Kanto district and Hokuriku district of Honshu. The fern grows in the deciduous broad-leaved forest zone in the mountains and is 20 to 30 cm high. The leaves are remarkably dimorphic between fertile fronds and sterile fronds, and fertile fronds are about twice as long as sterile fronds. The petiole and the back of the leaf axis are dark purple-brown, with dense fine dots, and the texture is rough. The petiole is densely populated with linear scales.  青森市荒川「八甲田山」にて、2019年08月29日撮影。  Shu Suehiro shu@botanic.jp