The Identity of Nephrodium malabariense Fee

Abstract

Summary. Fee's Nephrodium malabariense does not differ significantly from Christella dentata. An examination of 16 sheets of specimens linked with the original description has shown them to consist of a mixture of Christella dentata and C. dentata x parasitica. A lectotype is selected, in the absence of the holotype, and the name included in the synonymy of C. dentata. An isotype of Dryopteris meeboldii has been located and this confirms its specific identity with N. malabariense and hence its inclusion in the synonymy of C. dentata. Fee (1865) based his description of Nephrodium malabariense on part of a gathering distributed by Kew. The geographical origin of the fern was Peninsular India, the identification on the label was Nephrodium molle and the specimens distributed formed part of the duplicate material of J. D. Hooker and Thomson's Indian collection. Hooker and Thomson did not themselves collect in southern India and they received the Nephrodium from Stocks and Law by one of whom it had been collected. The present location of Fee's holotype is not known but several other specimens carrying the same label and identification were sent out by Kew about the same time and through the courtesy of the curators of the herbaria at Kew, British Museum (Natural History), Edinburgh, U.S. National Herbarium, Berlin, Paris, Geneva, Leiden and Utrecht I have been able to examine 16 sheets of this south Indian fern presumed to be the same as that on which Fee founded his new species. Nephrodium molle (Sw.) R. Br. was construed by Hooker (1862) in the 'Species Filicum' and by Hooker and Baker (1867) in the 'Synopsis Filicum' in a very wide sense covering the species currently named Christella parasitica (L.) L6v. and C. dentata (Forssk.) Brownsey & Jermy (or Cyclosorus parasiticus (L.) Farw. and C. dentatus (Forssk.) Ching). F6e construed N. molle in a narrower sense which excluded C. parasitica so that when he described Nephrodium malabariense he was distinguishing it from C. dentata. The description of his new species however does not contain a single qualitative characteristic which marks it off from C. dentata. The main distinctions are stated to be: 'plus dlancee, plus raide, beaucoup moins velue avec indusium presque glabre.' These are all quantitative differences of unproved fixity and doubtful systematic significance in a genus wherein at least some species (including C. dentata) display a range in degree, if not in type, of pubescence and several species may have either glabrous or hairy indusia. In his recent account of the genus Christella Sect. Christella, Holttum (1976) maintains Fee's malabariense as a distinct species which he credits with a distribution stretching from southern India and Ceylon to south China. But the distinctions on which Holttum relies are again differences of degree and not of kind and since the widely distributed and polymorphic C. dentata shows a range of intraspecific variation in respect of size, texture, depth of