【摘要】 <正> 宽带蕨属 新属 Platygyria Ching et S.K.Wu,gen nov. Genus novum ex affinitate Lepisori(J.Sm.)Ching,a quo differt plantaaestivali herbacea,frondibus forma variis,simplisibus margine sinuatis usquehastato-palmatis aut basl unilateraliter paulo auriculatis;sporangiis globosis(nec pyriformibus),annulo verticali latissimo completo e cellulae pariete paulovel vix incrassata compositis;sporis reniformi-oblbngis monoletis sporodermislaeyibus.更多还原

【Abstract】 The present paper has shown that Ncocheiropteris waltonii Ching (Hook. Ic. P1. t. 3168. 1932) is a peculiar polypodiaceous fern. It does not belong to the monotypic Chinese genus Neicheiropteris Christ at all, nor to any other known genera of the family Polypodiaccae, because of its distinctly globose sporangia with a very broad vertical complete annulus consisting of cells of scarcely indurated cell-walls and indistinct stomium, as shown in the original publication, As there was then only a couple of extant specimens at the herbarium, Kew, where the senior author detected this fern around 1930’s, while working on the Himalayan ferns, no further study on this peculiar fern has since been made. Now we have at our disposal ample material of this species and other related ones from the Tibetan Plateau, whose flora of Pteridophytes has been in preparation for many years and will soon be published, and decide to give it a new generic rank, Platygyria, signifing the sporangia with broad annulus.As shown in the above diagnosis, the genus Platygyria distinguishes itself from all other polypodiaceous genera by the very broad vertical complete annulus of scarcely incraasate cell-walls; its affinity, however, with Lepisorus, especially L. clathratus is very evident in the thin herbaceous summer-green fronds and the characteristically clathratc rhizome-seales consisting of large hexagonal transparent luminae with long-protruding teeth on the margin. On the other hand, the genus further differs from Lepisorus in the young sori covered not by umbrella-shaped peltate, but by irregular or even ovate-lanceolate para-physes, not quite peltatly affixed.The genus is now represented by two distinct species, P. waltonii and P. sinuata from the Tibetan Plateau. But what is more is that there have been found two others taxa with intermediate characters, i. e. their fronds are simple and entire like L. clathratus, but with base of lamina narrowly unequally cuneate and often blunt apex and the majorty of sporangia with very broad annulus, but intermixed with some sporangia with normal polypodioid annulus. These forms are found quite common throughout the Himalayan region (inclubing N. W. India) and Southwestern China (Yunnan and Szechuan) and they in herbaria have always been wrongly named as Lepisorus clathratus (Clarke) Ching. This seems to clearly indicate that they are hybrids between Platygyria and Lepisorus clathratus pending the cyto-genetic study. In view of the presence of very broad vertical complete sporangiate annulus and the irregular or even ovate-lanceolate paraphyses in the sori, Platygyria may perhaps be considered as a primitive taxon in the family Polypodiaceae subfamily Lepisorioideae.AcknowledgementWe should like to tender our best thanks of gratitude to Professor R. E. Holltum, Kew Herbarium, who in response to our inquiry took time to check up the Kew bundle of Lepisorus clathratus specimens and wrote ( 9 April, 1979) a very informative report on his findings.更多还原