摘要
描述一种采自湖北上泥盆统弗拉阶黄家蹬组中的石松植物。该植物茎轴纤细。叶基纺锤形,螺旋排列。叶线形,叶缘具刺。具顶生的孢子叶球。其孢子叶匙状或披针形,边缘具刺。孢子囊呈圆形或椭圆形。植物茎具原生中柱。原生木质部呈小脊状位于中柱边缘。后生木质部管胞由梯纹分子组成,在加厚棒之间没有类似“威廉姆逊纹”的连接物。该植物与采自湖南中泥盆统基维特阶的Longostachys(Zhu,Huand Feng) Caiand Chen可比较。它们在茎轴、线形和具刺的叶、纺锤形和螺旋排列的叶基、匙状披针形的孢子叶,以及叶、叶基和孢子叶的度量等特征方面均非常相似。两者在解剖特征上存有差别,即当前植物不具次生木质部,不具髓,后生木质部加厚棒之间不具连接物。考虑到现有特征并不足以建立新属种,暂归入cf.Longostachyssp.
A lycopsid plant with preserved morphology and anatomy is described from the Huangjiadeng Formation （Frasnian） of Hubei Province. Its stems are slender. The leaf bases are spindle in shape, and arranged in helices. Leaves are persistent and spiny. This plant bears distal cones. Sporophyll is spoon-like and lanceolate in form, with spines along its margins. Sporangia are circular or elliptical in surface view. In anatomy, the stem has a solid strand of exarch primary xylem. Protoxylem tracheids, composed of annular or helical elements, appear as minute ridges on the stele periphery. Metaxylem tracheids are composed of scalariform elements, showing no connecting ＂Williamson＇s striations＂ between the bars. The shared characteristics of the present plant and Longostachys （Zhu, Hu and Feng） Cai and Chen, from the upper Middle Devonian （Givetian） of Hunan Province, lie in linear and spiny leaves, spindle-shaped and helically arranged leaf bases, spoon-like or lanceolate sporophylls; further more, the dimensions of leaves, leaf bases and sporophyll are also quite alike. However, they show differences in some anatomical characteristics; the present plant bears no secondary xylem, no pith, and no connecting materials between thickened bars of metaxylem tracheids. The preserved characteristics, however, are incomplete for establishing a new species. We temporarily assign our specimens to el. Longostachys sp.
出处
《古生物学报》
CAS
CSCD
北大核心
2007年第2期183-194,共12页
Acta Palaeontologica Sinica
基金
国家自然科学基金(40232019)
全国博士学位论文作者专项资金资助项目(200429)
教育部博士点基金资助
