Kuramagoke - Kuramagoke

An evergreen fern of the Selaginellaceae family. It is a small herb that grows in mountain forests throughout Japan and at first glance appears moss-like. The stems are thin and branch out like forks while crawling along the ground, producing white thread-like rhizophores (root-like bodies) at the branching points, from whose tips roots emerge. The leaves are scale-like and arranged in a total of four rows, with lateral leaves on the left and right and dorsal leaves in two rows on the back. The lateral leaves are oval, while the dorsal leaves are obliquely long oval and press against the stem. Sporophylls are densely packed at the tips of the twigs to form spikes. There are two types of sporophylls, with megasporangia and microsporangia at the base of the upper surface. The name comes from Mount Kurama, where it was first discovered. The closely related species, S. nipponica , is found in warm regions west of the Kanto region, with broad ovate lateral leaves, upright branches bearing sporophylls, and no distinct spikes. S. uncinata is native to southern China and is evergreen. It has thick stems, densely branched lateral branches 2-3 times, and leaves that overlap each other. In the shade, the leaves shine like metallic blue. It is easily propagated by cuttings, but is sensitive to frost, so it is mostly cultivated in greenhouses. It was introduced to Japan at the beginning of the Meiji period.

[Makoto Nishida]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

イワヒバ科の常緑性シダ。各地の山林中に生える小形草本で、一見、コケ状となる。茎は細く、叉状(さじょう)分枝しながら地表をはい、分枝点から白色糸状の担根体（根状体）を生じ、その先端から根が出る。葉は鱗片(りんぺん)状で、左右につく側葉と背面に2列につく背葉とがあり、計4列に並ぶ。側葉は卵形、背葉は斜めの長卵形で茎に圧着する。小枝の先端部に胞子葉が密集して穂をつくる。胞子葉は2型で、上面基部に、それぞれ大胞子嚢(ほうしのう)と小胞子嚢を生ずる。名は最初の発見地、鞍馬(くらま)山に由来する。近縁種のタチクラマゴケS. nipponicaは関東地方以西の暖地に分布し、側葉は広卵形、胞子葉をつけた枝は直立し、はっきりした穂をつくらない。コンテリクラマゴケS. uncinataは、中国南部原産で常緑。茎は太く、側枝は密に2～3回分枝して葉が互いに重なり合う。葉は日陰で青藍(せいらん)色の金属様に光る。挿芽で容易に繁殖するが、霜に弱いので、多くは温室内で栽培する。明治の初めに渡来した。

［西田　誠］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例