Taxonomic studies in the Aganisia complex (Orchidaceae, Zygopetalinae)

Abstract

The Aganisia complex (Orchidaceae, Epidendroideae, Cymbidieae, Zygopetalinae), which comprises the genera Aganisia, Cheiradenia, Koellensteinia, Otostylis and Paradisanthus, are all revised except Koellensteinia, for which a synopsis is proposed. We reviewed 109 generic, sectional, specific and infraspecific names. Of these, five are for the first time listed as names in scheda. We propose two new combinations, 17 new synonyms, 30 typifications, and two types for which the category is corrected. Doubtful, misapplied and non-applicable names are also treated. We recognize three species and two forms of Aganisia, one species of Cheiradenia and Paradisanthus, eleven species of Koellensteinia and two species Otostylis. The Aganisia complex is completely South American, with exception of K. tricolor, which also occurs in Belize, and A. pulchella, C. cuspidata and K. graminea, in Trinidad. Aganisia and Otostylis occur predominantly in lowland areas of western and northern South America; Cheiradenia in Trinidad and the Guianas Shield; Paradisanthus mainly on the coast of eastern and southern Brazil; and Koellensteinia the most widely distributed, occurring predominantly in South America strictly north of the Tropic of Capricorn. Aganisia and Cheiradenia grow in rainforests; Paradisanthus in rainforests and coastal vegetation; Otostylis in grassy areas; and Koellensteinia in all of these.