Flora of Viçosa, Minas Gerais State, Brazil: the ancient fern orders Gleicheniales and Osmundales (Polypodiopsida)

ABSTRACT In the Municipality of Viçosa, one family, three genera, and five species of Gleicheniales occur: Dicranopteris flexuosa, Gleichenella pectinata, Sticherus bifidus, S. lanuginosus, and S. nigropaleaceus (Gleicheniaceae). All these species are very common in the area, forming dense thickets (“gleiquenais”) in disturbed areas, and co-occurring in these thickets. Dicranopteris flexuosa, G. pectinata, and S. bifidus are widespread in the Neotropics; Sticherus lanuginosus is widespread in South America and Costa Rica; and S. nigropaleaceous is endemic to the Brazilian Atlantic Forest. We provide nomenclatural corrections for S. lanuginosus. In Osmundales, only one species is found in Viçosa, occurring in marshes: Osmunda palustris (Osmundaceae). The taxonomy of Osmunda is still controversial, with the main Brazilian taxon named as O. palustris, O. regalis, O. regalis subsp. palustris, O. regalis var. spectabilis, O spectabilis, or O. spectabilis var. palustris. In our view, the best name for the taxon occurring in Viçosa is O. palustris, a taxon likely with a Neotropical distribution. Our taxonomic judgment is based on the re-interpretation of recent phylogenetic works, together with populational and morphological studies comparing Brazilian specimens with specimens from the U.S.A. We present descriptions, illustrations, examined specimens, taxonomic comments, and keys to identification.