Monograph of Elaphoglossum sect. Polytrichia subsect. Apoda (Dryopteridaceae)

Abstract

Abstract— We present a monographic treatment for the 13 species of Elaphoglossum sect. Polytrichia subsect. Apoda (Dryopteridaceae). Molecular phylogenetic analyses have recovered this subsection as monophyletic within the so-called “subulate-scaled clade” of Elaphoglossum. Morphologically, the species of E. subsect. Apoda are usually characterized by the presence of brightly colored stem scales (yellowish, orangish, or reddish, as opposed to castaneous to black), evenly distributed subulate scales on laminar surfaces, tiny glandular hairs on different parts of the leaves, and adult sterile leaves without hydathodes. The species can be divided into two groups: one with subsessile and the other with long-petiolate leaves. Elaphoglossum subsection Apoda is distributed from southern Mexico and the Antilles to Bolivia and midwestern Brazil. Elaphoglossum atehortuae, a new species from the Amazon region of Ecuador, is described, illustrated, and compared to its most similar species. It is unusual within this group for lacking subulate scales on both surfaces of the laminae, a character state that it shares with E. backhouseanum. Two species, E. polyblepharum and E. trichophorum, are included in the group for the first time, whereas E. procurrens and E. siliquoides are excluded based on morphological characters and previously published molecular phylogenies. We also provide comments for E. ×morphohybridum, which is a hybrid between E. alvaradoanum and E. crinitum. Lectotypes are designated for Acrostichum apodum, A. platyneuron, A. cubense, A. procurrens, A. trichophorum, and Elaphoglossum auripilum, and epitypes are designated for A. apodum. To facilitate the identification of species, we provide keys, descriptions, illustrations, comments, synonyms, distribution maps, spore images, and a list of specimens examined.