Leaves not 3-veined from the base. Stipules inconspicuous, early deciduous. Leaves entire, glabrous. Plants with spinose branches, leaves thick. C. spinosus 5b.
Plants never spinose, leaves thin.
C. integerimus 4b. Leaves toothed or serrate, pubescent at least underneath, glandular, papillate on upper surface. Plants erect, 4-15 feet high C. papillosus 5b. Plants low, 1-3 feet high C. papillosus ssp. Stipules persistent, swollen and corky at the base of the leaves.