Clarification of Prosthechea guttata (Orchidaceae) and description of an “old” new Prosthechea species from southern Mexico and Guatemala

Abstract

Background: Epidendrum guttatum A.Rich. & Galeotti, based on specimens collected by Galeotti in Mexico in 1840, was predated by E. guttatum L. and replaced by Encyclia guttata Schltr. and subsequently by superfluous Epidendrum maculosum Ames, F.T.Hubb. & C.Schweinf. Questions: The study aimed to show that the concept of Prosthechea guttata of recent authors was based on a misinterpretation of its type material, resulting in the application of the name to a different, undescribed species. Studied species: Prosthechea guttata (Schltr.) Christenson and P. sanchezii Salazar, R.Jiménez & T.L.Vieira. Study site and dates: Southern Mexico and Guatemala, 2004-2024. Methods: Study of type material and its comparison with recent collections; field work; documental and herbarium research. Results: The identity of Epidendrum guttatum A.Rich. & Galeotti (now Prosthechea guttata) is clarified, showing that recent authors have misinterpreted that morphologically distinctive species restricted to the Sierra Madre del Sur, Oaxaca, Mexico, confusing it with an undescribed species distributed east of the Isthmus of Tehuantepec in Oaxaca and Chiapas, Mexico and in Guatemala. The latter is proposed here as a new species, Prosthechea sanchezii, distinguished from genuine P. guttata, and all other Prosthechea species, mainly by the echinate-warty crests on the outer surface of the sepals. Conclusions: Prosthechea guttata and P. sanchezii are two distinct species historically confused but easily distinguished by morphological attributes, each distributed on opposite sides of the Isthmus of Tehuantepec.

Keywords

• Epidendrum guttatum
• Oaxaca
• Prosthechea maculosa
• Prosthechea sanchezii
• Sierra Madre de Chiapas
• Sierra Madre del Sur