Monograph of the West Indian fern genus Polystichopsis (Dryopteridaceae)

Abstract

Keys, full synonymy, descriptions, specimens examined, and illustrations are provided for the fern genus Polystichopsis. The genus occurs in the West Indies, with disjunct populations in Nicaragua and Isla Margarita, Venezuela. Seven species and one hybrid are recognized. The genus can be distinguished from other dryopteroid genera by the combination of creeping rhizomes, distichous leaves, lack of scales on the mature leaves, and straight, whitish multicellular hairs on the leaves. Although the genus has creeping rhizomes, it does not climb as do many other closely related dryopteroid genera. A new species, P. puberula, and new hybrid, P. × sanchezii (=P. chaerophylloides × P. pubescens), are described. Lectotypes are designated for Nephrodium pubescens var. breviculum , P. leucochaete, and P. muscosa. A list is provided of 28 names excluded from Polystichopsis, and another list is provided for accepted names and their synonyms that apply in the genus.