A Revised Classification of Thelypteris Subgenus Amauropelta

Abstract

Thelypteris subgenus Amauropelta is a highly natural, probably monophyletic group occurring principally in the New World tropics and subtropics. The number of species is large; Christensen (1907, 1913) recognized about 120, and 55 have been described since then. Many undescribed species remain. The size of the subgenus in terms of both the number of good species (perhaps 200) and the number of basionyms assignable to the subgenus (ca. 400) makes it desirable that an infrasubgeneric classification be achieved before a revision of closely related species groups is undertaken and before additional species are described. Christensen made no attempt to subdivide subg. Amauropelta (his Dryopteris subg. Lastrea), but he did recognize small groups of closely related species. As a result of my studies, I feel that the species fall naturally into nine more or less distinct groups, to be given the rank of section. There are relatively few basionyms that must remain unplaced, either because of intermediacy between sections or because type material has not yet been seen. I have attempted to account for all basionyms (based on New World specimens) that should be included within the circumscription of subg. Amauropelta. No doubt a few have been missed, especially infraspecific names. The search has been difficult because species have been described under so many different genera and because of the huge number of species in Thelypteris s.1. (perhaps 1000). An asterisk following a name in the enumeration of basionyms indicates that I have seen type material. I thank R: E. Holttum for helping with the Latin diagnoses and curators of the following herbaria for loan of types: A, B, DS, F, GH, HB, K, M, R, SI, S, S-PA, US. S-PA, U. TAXONOMIC CHARACTERS