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| Polystemma margaritadelacerdae J. Martínez-Ramírez, L.O. Alvarado & Ocampo, in Ocampo, Martínez-Ramírez et Alvarado-Cárdenas, 2025. |
Abstract
Background: Polystemma has about 27 species distributed from southeastern United States to central Costa Rica. Plant collecting activities detected one taxon that does not fit the description of previously known species of the genus.
Methods: Recently collected plant material was studied to prepare a morphological description. The conservation status of the new taxon was evaluated, following the IUCN Red List criteria.
Results: Polystemma margaritadelacerdae is proposed as a new species because of the presence of a green corolla, an exserted cylindrical gynostegial corona, with a fimbriate to denticulate lobe apex. At the moment, the new taxon is categorized as Vulnerable (VU).
Conclusions: A new species of Polystemma is described and the number of Apocynaceae species that occur in Aguascalientes increases to 25.
Keywords: Asclepiadoideae, central Mexico, subtropical shrubland, taxonomic novelty
Polystemma margaritadelacerdae J. Martínez-Ramírez, L.O. Alvarado & Ocampo, sp. nov.
Diagnosis. The new species is similar to Polystemma pueblensis by its green corolla and exerted gynostegial corona; it differs by its cylindrical corona (vs. campanulate) and by the presence of an internal and external gynostegial corona with lobes apically fimbriate to denticulate (vs. rugulose to verrucose).
Gilberto Ocampo, Julio Martínez-Ramírez and Leonardo O. Alvarado-Cárdenas. 2025. A New Species of Polystemma (Apocynaceae) from Aguascalientes, Mexico. Botanical Sciences. 103(1); 311-318. DOI: doi.org/10.17129/botsci.3600