- clump-forming cactus with stems usually six inches long or less, the outer stems in a clump often nearly prostrate
- stems usually 1-2 inches in diameter, with 7-9 "ribs" (ridges) of tubercles
- spines of various lengths
- flowers lemon-yellow, reddish toward center
- two varieties known from south Texas: var. papillosus and var. angusticeps
- difficult to distinguish between the two, but both varieties are rare
