めやぶそてつ (雌藪蘇鉄) [Index] [Back]

Cyrtomium caryotideum

Cyrtomium caryotideum

Cyrtomium caryotideum

Cyrtomium caryotideum

Cyrtomium caryotideum

Cyrtomium caryotideum

Cyrtomium caryotideum

わが国の本州、関東地方以西から四国・九州、それに台湾やフィリピン、ヒマラヤ周辺、ハワイ諸島などに分布しています。おもに石灰岩地域にまれに生え、高さは40~80センチになります。葉は単羽状複葉で黄緑色から緑色、やや光沢があり、硬い紙質です。側羽片は2~6対つき、基部の前側または両側に耳状突起があります。羽片の先端は尾状にのび、辺縁には鋭い鋸歯があります。ソーラスは円形で中肋よりにつき、包膜は灰白色または中心部が暗褐色です。本種は3倍体の単為生殖で、染色体数は n=123 です。台湾華語では「細葉貫眾蕨」と呼ばれます。
オシダ科ヤブソテツ属の常緑性シダ類で、学名は Cyrtomium caryotideum。英名はありません。
The "Me-yabu-sotetsu" (Cyrtomium caryotideum) belongs to the family Dryopteridaceae. It is an evergreen fern that is distributed from the Kanto region of Honshu westward to Shikoku and Kyushu in Japan, as well as Taiwan, the Philippines, the Himalayas, and the Hawaiian Islands. It grows in limestone areas and is rarely found, reaching a height of 40 to 80 cm. The leaves are pinnate compound, yellowish-green to green, slightly shiny, and have a stiff papery texture. There are 2 to 6 pairs of lateral pinnae, and auricles are present on the front or both sides of the base. The tips of the pinnae are elongated into a tail, and the margins are serrated. The sorus is round and attached to the midrib, and the indisum is grayish white or dark brown in the center. This species is a triploid parthenogenetic plant with n=123 chromosomes. In Taiwanese, it is called "細葉貫眾蕨".
茨城県つくば市「つくば実験植物園」にて、2025年01月25日撮影。

Shu Suehiro
shu@botanic.jp