A systematic revision of the Encyclia adenocarpos complex (Orchidaceae: Laeliinae) from Megamexico, including two new species from Mexico

Abstract

The Encyclia adenocarpos complex is restricted to the Pacific slopes of Megamexico, from Sonora, Mexico, to northern Nicaragua. It is characterized by pyriform to suborbicular pseudobulbs, (1-)2-3(4) thickly coriaceous, narrow leaves (> 15 times longer than wide), thin, verruculose inflorescences, and a verruculose ovary. The column is broad and wingless, fused to the labellum at its proximal 1/4. The flowers of the Encyclia adenocarpos complex feature what is here dubbed the Tupperware© labellum-column morphology, where the columnar ventral face is concave and fits tightly around the rim or upper margins of the callus, similar to the seal of this plasticware. All species grow on dry forests at low elevations from sea level to ca. 1500 m; most populations occurring below 500 m. The complex consists of six species, two of which are newly described herein: E. acapulcensis sp. nov., from southern Guerrero and E. enriquearcilae sp. nov., from western Oaxaca and neighboring Guerrero, Mexico. Encyclia rodolfoi is the correct name for populations of the Tehuantepec Isthmus whereas E. × nizandensis is here regarded as a natural hybrid between E. rodolfoi and E. parviflora; the evidence is presented and discussed. Encyclia schaeferi is treated as a morph of E. papillosa and included in its synonymy. A neotype is selected for Epidendrum adenocarpos and Epidendrum crispatum is rejected as a synonym thereof. All species are illustrated and discussed, and a key to the species is presented. Furthermore, the conservation status of each species is analyzed under the IUCN methodology. Other aspects of the biology of this complex are also discussed.