Asclepias sanjuanensis Heil, Porter, & Welsh, a new species from the pinyon-juniper woodlands of the San Juan River Valley, San Juan County, New Mexico, is described and illustratred. The species appears to be local and rare. Similar to A. ruthiae Maguire, it is distinguished by the greater number of flowers per inflorescence, the larger number of stems, and the pubescence characters.
Heil, Kenneth D.; Porter, J. Mark; and Welsh, Stanley L.
"A new species of Asclepias (Asclepiadaceae) from northwestern New Mexico,"
Great Basin Naturalist: Vol. 49
, Article 11.
Available at: http://scholarsarchive.byu.edu/gbn/vol49/iss1/11