The Status of the Genus Asclepias in New Mexico

The genus Asclepias contains about 120 species, most of which are native to the Americas. A recent summary of the genus in New Mexico lists 31 taxa. There have been several additions to the group since the publication of Martin and Hutchins A Flora of New Mexico. Below are a few comments on the group, and updated key to the species, and distribution maps for each taxon. Since the late nineteenth century New Mexico has been carrying a phantom taxon in its flora, Asclepias scaposa. No specimens exist in local herbaria. Its presence in New Mexico depends on a single sheet at the Missouri Botanical Garden. R.E. Woodson, in his 1954 monograph of the genus Asclepias, describes the problem: Asclepias scaposa has been rather an enigma since its description from a single fruiting specimen by Miss Vail in 1898. This, which remains the only specimen recorded from the United States [no longer the case] as well as the only fruiting specimen of the spe-cies, was found duplicated in both the Gray Herbarium and the herbarium of the New York botanical Garden without a number; in the herbarium of he Missouri Botanical Garden a third duplicate bears the number 7, which probably is an arbitrary number assigned by Engelmann and not a field number in the true sense. Without a field num