Calamites (English spelling)

Japanese: カラミテス（英語表記）Calamites

A representative genus of the ferns in the Loboraceae family of the Loboraceae order. A tall tree that can reach 15m in height. It has a large pith hole in the center, and the xylem undergoes secondary thickening growth. Both the trunk and branches are divided into many internodes, with smooth surfaces and somewhat indistinct vertical lines. Usually, what is found as a fossil is the external shape of the pith hole, so the patterns seen on the surface are female molds on the inner surface of the pith hole, and what looks like a node is a nodular partition on the inner surface of the pith hole. The longitudinal ridges of the internodes are impressions of the pitted pith where the cells have decayed and become depressed, and the alternating longitudinal grooves are impressions of the xylem protruding into the pith hole. The small circular or elliptical projections (subnodal markings) just below the nodal lines at the top of the longitudinal ridges are not traces of branch legs or vascular bundles, but impressions of the depressed parts due to the presence of special parenchyma cells. The internode ridges and longitudinal grooves alternate in adjacent nodes. The flowers are spike-shaped, each spore leaf is shield-shaped, and the spores vary in size. It is extremely abundant in the Carboniferous of Europe, but rare in East Asia. It is distributed from the Lower Carboniferous to the Upper Permian.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

シダ植物のロボク (蘆木) 目ロボク科の代表属。高さ 15mに達する高木。中心に大きな髄孔があり，木部は二次肥大生長をする。幹，枝ともに多数の節間に分れ，その表面は平滑で，やや不明瞭な縦線がある。普通化石として産出するのは髄孔内の外形化石で，したがって表面にみられる模様は髄孔内面の雌型で，節のようにみえるのは髄孔内面の節状仕切り。節間の縦走隆起帯は細胞が腐ってへこんだ射出髄部の押し型で，これと交互する縦溝線は髄孔内に突出した木部の押し型である。縦走隆起帯の上端で節線の直下にある円形ないし楕円形の小突起 (節下紋) は分枝脚や維管束の跡ではなく，特殊な柔細胞の存在のために，特にへこんだ部分の押し型である。節間の隆起部と縦溝線とは，相隣る節では交互する。花は穂状で，各芽胞葉は楯形，芽胞には大小の別がある。ヨーロッパの石炭系にはきわめて豊富に産するが東アジアでは稀種。下部石炭系から上部ペルム系まで分布する。

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