Family: Milkweed (Asclepiadaceae)
Size: To 0.5 in. wide in clusters to 1.5 in. wide
Other names: Whorled milkweed
Notes: 27 species of Asclepias in Arizona.
Western whorled milkweed entry in the online edition of An Illustrated Guide to Arizona Weeds, Kittie F. Parker, University of Arizona Press.
This plant is found on the Appleton-Whittell Research Ranch Working Check list of flora.