Rose, Contributions from the U. S. National Herbarium 12: 402, 1909
Opuntia toumeyi is a low but not prostrate, bushy species with pads narrowed towards the base. The plant often appears yellowish-green and has brownish-white or white spines. Clumps of the plants seem yellowish compared to other Opuntia species. Glochids are red-brown or paler. There is often one central spine that is dominant and longer than all the other spines in an areole (sometimes it is missing on some pads but rarely all pads, and sometimes there is more than one). Spination is similar to that in O. flavispina, but the spines are not true yellow, and the long spine is not reflexed so intensely. O. toumeyi is lower and more spreading than O. flavispina. O. toumeyi grows in the gravelly foothills and mountains in southern Arizona and in Sonora, Mexico. Flowers are bright yellow, sometimes with a bit of orange; they may change to orange or even reddish on day two. The stigmas are green, and the filaments are yellow. See the original citation.