とらのおしだ (虎の尾羊歯) [Index] [Back] わが国の各地をはじめ、台湾や朝鮮半島、中国、シベリア東部に分布しています。やや乾燥した林縁や道ばたに生え、高さは１０〜３０センチになります。葉はやや２形で、胞子葉は長く、栄養葉は短く、地表近くに生えます。葉身は披針形の単羽状から２回羽状複葉で、下部の羽片は短く耳状になります。ソーラスは長楕円形で、中肋寄りに斜めにつきます。台湾華語では「縮羽鐵角蕨」、中国語では「虎尾鐵角蕨（hu wei tie jiao jue）」と呼ばれます。 チャセンシダ科チャセンシダ属の常緑性シダで、学名は Asplenium incisum。英名は Split-leaf spleenwort、Forked spleenwort。 The Split-leaf spleenwort (Asplenium incisum) belongs to Aspleniaceae (the Spleenworts family). It is an evergreen fern that is distributed throughout Japan, as well as in Taiwan, the Korean Peninsula, China, and eastern Siberia. It grows along slightly dry forest edges and roadsides, reaching a height of 10 to 30 cm. The leaves are somewhat dimorphic: the sporophylls (fertile fronds) are long, while the trophophylls (sterile fronds) are short and grow close to the ground. The leaf blades are lanceolate, ranging from simple pinnate to twice-pinnately compound, with the lower pinnae being short and ear-shaped. The sori are oblong and attached obliquely near the midrib. In Taiwanese Chinese, it is called "縮羽鐵角蕨", and "虎尾鐵角蕨" (hu wei tie jiao jue) in Chinese. 宮城県仙台市太白区秋保町馬場「秋保大滝植物園」にて、2026年07月28日撮影。 Shu Suehiro shu@botanic.jp