A Reclassification of the Fern Genus Pyrrosia

Abstract

The name Pyrrosia, although published by Mirbel in 1803, was overlooked by pteridologists until relatively recently. Instead, the synonyms Cyclophorus Desv., 1811, or Niphobolus Kaulf., 1824, were used. Giesenhagen (1901) published the only monograph, treating 50 species in Niphobolus and describing their venation, epidermis, and indument. Farwell (1931, pp. 241-246) recognized that Pyrrosia is the correct name of the genus. R. C. Ching (1935) studied the species of the Asian mainland, Japan, and Taiwan Province of China. He transferred 49 known species to Pyrrosia and described five new species. This has been the only extensive systematic paper on the genus. Nayar and others (1961, 1965, 1967) did detailed work on the morphology and anatomy of the Indian species of Pyrrosia in which they divided the 13 Indian species into six groups, some of which are apparently unnatural and inconvenient to use. For example, they placed P. lingua (Thunb.) Farw., which has stellate hairs with only lanceolate arms in the P. heteractis group, although each stellate hair of P. heteractis (Mett. ex Kuhn) Ching has 1-3 longer, acicular arms in addition to the lanceolate arms. Van Alderwerelt van Rosenburg (1908, pp. 678-696) divided 34 Malesian species into two sections under the generic name Cyclophorus. Section Niphobolus had venation similar to that of Campyloneurum (more or less regular, subquadrangular areolae with two or more simple or forked, included, extrorse veinlets). Section Niphopsis had venation similar to that of Pleopeltis (more or less irregularly netted with single, free, included, variously oriented veinlets). This arrangement has something to recommend it, but since the blade of Pyrrosia is very thick and in most species the veins cannot be seen without clearing, venation is difficult to use for identifications.