(Anthony) Ferguson, Cactus and Succulent Journal (U.S.) 58(3): 124, 1986
Opuntia chisosensis occurs only in the Big Bend region of Texas and adjacent Mexico where it grows at higher elevations in wooded areas and where it is a distinctive Opuntia. At one time it was known as O. lindheimeri chisosensis. There are 1-5 spines per areole in this Opuntia, spreading, yellow to orange, tipped yellow, darkening with age (at higher elevations), or dark red-brown (lower elevations). The spines are more or less acicular, 2 to 6.7 mm, terete or flattened near the base, and often curved. Spines generally occur in the upper portions of the cladodes. Glochids may partly encircle the areoles and are also in a poorly formed apical tuft. Flowers on this Opuntia are 2- to 3-inches wide and yellowish or yellow-buff. The stigma is green above a yellow style; filaments are pale green. Read a technical description of O. chisosensis at the Flora of North America online. More information about this prickly pear can be found in Weedin and Powell (2004). O. chisosensis is diploid.