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Type: Article
Published: 2023-09-13
Page range: 194-200
Abstract views: 264
PDF downloaded: 17

Polystemma stevensii (Apocynaceae, Asclepiadoideae), a new species from Michoacán, Mexico

Centro Universitario de Ciencias Biológicas y Agropecuarias; Universidad de Guadalajara; Camino Ing. Ramón Padilla Sánchez 2100; Las Agujas 45200; Zapopan; Jalisco; Mexico
Centro Universitario de Ciencias Biológicas y Agropecuarias; Universidad de Guadalajara; Camino Ing. Ramón Padilla Sánchez 2100; Las Agujas 45200; Zapopan; Jalisco; Mexico
Instituto de Ecología; A.C.; Centro Regional del Bajío; Av. Lázaro Cárdenas 253; 61600 Pátzcuaro; Michoacán; Mexico
Eudicots Gonolobinae Balsas Depression endemic


Polystemma stevensii, a new species from Michoacán, Mexico, is described and illustrated. It grows in tropical deciduous forest in the Balsas Depression at elevations from 350 to 750 m. Polystemma stevensii is similar to P. viridiflorum but differs by having a gynostegial corona with five lobes fused at the base to form a discontinuous flat ring (vs. not forming a discontinuous flat ring), an internal corona with two deltate lobes (vs. with one ligulate lobe), and globose style head (vs. flat style head). A distribution map of the new species and a key to determine the Polystemma species of Michoacán are provided. Following IUCN Red List guidelines, it is assigned a preliminary category of endangered, EN B1ab(i,ii,iii)+2ab(i,ii,iii). Polystemma now includes eight species, of which five are endemic to Mexico.



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