The Lindsaeoid ferns of the Old World II. A revision of Tapeinidium

Tapeinidium is the second largest of the Lindsaeoid fern genera. In the present study 17 species are distinguished. Until Tapeinidium was recognized as a genus its species were included in Microlepia, where it was originally described as an infrageneric division, or in Davallia. Fée (1852), then Diels (1902), treated it as a genus, but under the incorrectly interpreted name Wibelia Bernhardi, which is actually a synonym of Davallia (see Copeland, 1947). The species described so far have mainly been distinguished by their leaf architecture, especially the degree of dissection; see, e.g., van Alderwerelt van Rosenburgh (1909). In my opinion this is at best one of several useful characters. At least equally important is the structure of the petiole and the other axes of the lamina, a character diat proved to be very valuable for diagnostic purposes in the neotropical Lindsaea species (Kramer, 1957a) but is much less serviceable in the paleotropical ones. In some cases the rhizome scales are also distinctive. These characters have been grossly neglected in the past, and the species distinguished by most authors are generally far too widely circumscribed. Diels (l.c.), for example, listed three species at a time when more than twice as many were known. Accordingly there proved to be a surprisingly large number of undescribed species, viz. 8 out of the 17 recognized here, some of them represented by numerous specimens in many herbaria and collected long ago but never recognized, e.g., T. novoguineense and T. melanesicum. This contrasts sharply with the situation in Lindsaea in the same region where the number of new species is comparatively very small and relatively many more species have to be placed in synonymy.