New Natural Hybrids and Nomenclatural Novelties in Catasetum (Orchidaceae) from the Guianas, Ecuador, and Peru

Resumen

One new Catasetum natural hybrid from Guyana is described and illustrated, Catasetum X guianense, and two taxa previously described as species are shown to be hybrids, Catasetum x sodiroi Schltr.and C. x violascens Reichb.f. & Warzc.The latter two are neotypified and lectotypified, re spectively.In addition, a lectotype is designated for Catasetum incurvum Klotzsch.An understanding of the pollination biology of Catasetum species assemblages and careful atten tion to reproductive isolation mechanisms have helped to distinguish species from natural hybrids (Dodson, 1962; Romero & Carnevali, 1992, and references therein).Here we present three natural hybrids from distinct geographical areas where species from Ca tasetum subg.Catasetum and Catasetum subg.Pseudocatasetum are found within euglossine bee flight range.The hybrids discussed encompass two of three possible combinations between these two groups: one between Catasetum longifolium Lindley (subg.Pseudocatasetum) and C. macrocarpum (subg.Catasetum , sect.Catasetum) from the Guian as; one between Catasetum macroglossurn and C. expansum (both in sect.Catasetum) from Ecuador; and one between Catasetum discolor Lindley (subg.Pseudocatasetum ) and C. incurvum Klotzsch (subg.Catasetum , sect.Catasetum) from Peru.