Two new Mexican species of Asclepias (Apocynaceae; Asclepiadoideae; Asclepiadeae)

Two new species of Asclepias from Mexico are described here: A. sauronii and A. graogramanii. The first species, from the states of Coahuila and Nuevo Leon, is morphologically similar to A. otarioides, but differs by its ovate-lanceolate to lanceolate leaves and its yellow corona with digitated and curved horns. The second species, distributed in Jalisco and Nayarit, is similar to A. glaucescens, but differs by its pink to white-pinkish flowers, its sessile gynostegium and its cylindrical to oblongoid, and rarely slightly conduplicate hoods. Descriptions, morphological comparisons, and geographic distributions of these species as well as a proposal of their conservation status are provided in this study. This discovery highlights Mexico as a center of diversity of the genus, with 75 species currently known in the country. Furthermore, 45.3% of those species are endemic to Mexico.