The genus Marsdenia (Apocynaceae: Asclepiadoideae) in Guerrero

The genus Marsdenia (Apocynaceae, Asclepiadoideae) is principally found in tropical and subtropical regions of the world and includes about 200 species. Mexico has 31 species; 8 are distributed in Guerrero State. This paper presents a key to species identification, descriptions, illustrations, distribution maps in the state, as well as conservation assessment for each species, according to the categories and criteria of the IUCN Red List (IUCN, 2001). The information is based on a critical study of herbarium specimens, principally from ENCB, FCME, MEXU and MO, in less degree materials housed at F, F, G, GH, IEB, K, LL, MICH, MIN, NY, PH and US, and field work.