Mammillaria macdougalii

A species formerly included in M. heyderi, common in the mountains near Tucson and Nogales, Arizona. It has been reported from extreme southwestern New Mexico, but, according to the Flora of North America, these reports cannot be verified. Unlike other members of the M. heyderi complex, M. macdougalii has fimbriate margins on its outer tepals.

A flowering plant at Peña Blanca Lake, Santa Cruz Co., Arizona, 19 Mar 2005.