宽带蕨属（水龙骨科）的系统学研究

对喜马拉雅和横断山地区特有的水龙骨科的宽带蕨属Platygyria Ching&S.K.Wu植物进行了形态学、分类学、生态和植物地理学的观察与分析，探讨了该属植物的系统位置、亲缘关系和生态适应性，推测宽带蕨属是随着喜马拉雅山脉的隆升，由瓦韦属Lepisorus（J.Sm.）Ching网眼瓦韦群植物适应高寒生态环境演化而来的新生类群。确定宽带蕨属有5种，即川西宽带蕨P.soulieana（Christ）X.C.Zhang&Q.R.Liu、多变宽带蕨P.variabilis Ching&S.K.Wu、耳基宽带

Systematics of Platygyria Ching & S. K. Wu (Polypodiaceae)

Platygyria Ching & S. K. Wu is a unique genus in Polypodiaceae. The striking feature of the species in the genus is the unusually broad and vertical complete annulus consisting of cells with scarcely incrassate cell walls and indistinct stomium in the globose sporangium, a very specialized character in Polypodiaceae. This small genus was not universally accepted and its species were merged into either Neocheiropteris Christ or Lepisorus (J. Sm.) Ching. A re-examination of this genus has shown that the sporangium character is rather stable in all of the species and within species, strongly supporting the treatment of these species as an independent group. Some micromorphological characters, such as rhizome scales, soral paraphyses and spore morphology are found to be useful for the delimitation of species. Five species are recognized in this genus, i.e. P. soulieana (Christ) X. C. Zhang & Q. R. Liu, P. variabilis Ching & S. K. Wu, P. inaequibasis Ching & S. K. Wu, P. sinuata Ching & S. K. Wu, and P. waltonii (Ching) Ching & S. K. Wu. All the species are distributed in the Hengduan-Himalayan mountains. The species of Platygyria form a natural group. They not only shares the unique characters of the leaf morphology, rhizome scales, soral paraphyses, sporangium, annulus and spores, but also have similar ecological amplitude and geographical distribution. Morphologically and phytogeographically, the genus is closely related to Lepisorus , especially to the sympatric Lepisorus clathratus group. The species of Platygyria might be descendants from the Lepisorus clathratus group during the uplift of the Himalayas.