TAXONOMIC REVISION OF THE NEOTROPICAL SPECIES OF ELAPHOGLOSSUM SECT. SQUAMIPEDIA (DRYOPTERIDACEAE)

Taxonomic keys, illustrations, descriptions, synonymy, distribution maps, and an index to collectors' names and numbers are given for the Neotropical taxa belonging to Elaphoglossum Schott ex J. Sm. sect. Squamipedia Mickel & Atehorhia. Eighteen taxa are recognized herein, consisting of 16 species, with one of the species, E. peltatum (Sw.) Urb., having three forms. Three new species are described: E. anthracinum A. Vasco, Mickel & R. C. Moran, E. blepharis A. Vasco, Mickel & R. C. Moran, and E. rhomboideum A. Vasco, Mickel & R. C. Moran. The following name is lectotypified: Acrostichum flabellatum Humb. & Bonpl. ex Wild. var. sphenophyllum Kunze. Four species are atypical in the genus by having divided laminae: E. colombianum (Maxon) Mickel and E. moorei E. Britton) Christ have pinnately divided laminae, E. peltatum (Sw.) Urb. has isodichotomously divided laminae, and E. tripartitum (Hook. & Grey.) Mickel has ternately divided laminae. The Neotropical species of the section can usually be distinguished from other species of Elaphoglossum by long-creeping, green rhizomes; thin, translucent, light orange or brown rhizome scales; distichous leaves; paired peglike aerophores on each side of the rhizome slightly proximal to the petiole bases; a lack of phyllopodia; leaves that are typically < 15 cm long; and echinulate spores. One species, E. nidiforme Mickel, is atypical by its large size and short-creeping rhizomes but is included here in Elaphoglossum sect. Squamipedia based on previous molecular phylogenetic analyses. All Neotropical species of Elaphoglossum sect. Squamipedia are epiphytes, usually in middle- to high-elevation forests. The section is most diverse in the Andes from Colombia to Bolivia, where 17 taxa occur.