Cylindropuntia acanthocarpa (buckhorn cholla) ( )

At first glance Cylindropuntia acanthocarpa is similar to Cylindropuntia echinocarpa or silver cholla, and the two may occur together. One way to separate them is to look at the shape of the tubercles, or raised mounds along the stem. In silver cholla the tubercles are never more than about twice are as long ass they are broad, while buckhorn cholla the tubercles are more elongate and their length is at least three times their width. Another difference is that the silver cholla has a distinctive main trunk that extends for a third to half of the height of the plant, while buckhorn cholla has a short trunk that forms no more than a fifth of the plant height, with branched stems above this point. In the springtime when the cacti are flowering, there is an easier way to separate the species. Silver cholla has greenish flowers while those of buckhorn cholla are typically reddish-purple to yellow. "California Desert Plants, Philip W Rundel, Robert J Gustafson, Micahel E Kauffmann."