A succulent unisexual, rarely bisexual, spiny plant, 1-5 ft. high, usually with only one main stem, but occasionally many branches from the base, freely or sparsely branched above, branches erect (occasionally falling over with age and again producing upright branches); root system of a few lateral branches spreading to 3-5 ft.; main stem or stems 1 1/2-3 ins. diam., branches 1/2-2 ins. diam. (incl. angles); angles usually 7-10, acute, 3-5 lin. high, very slightly toothed, glabrous, green becoming grey; leaves rudimentary, ovate lanceolate, pubescent below; spines (modified peduncles) thinly scattered or thickly placed along the angles, solitary, or two or three from a flowering eye (the solitary and scattered state is more usual in the female and the dense three-spine formation more common in the male), purplish, going grey with age; peduncles at the apex of the branches, minutely pubescent, 6-20 mm long, usually arising singly from the median position of the angle, or with two lateral peduncles, or two lateral spines from the base; peduncles (when only one from median position) simple or branched above and producing 1-2 lateral involucres from immediately below the initial involucre; bracts purple, several, increasing in size from the base, minutely pubescent on the lower surface and ciliate on the margin; male involucre 5-6 mm in diam., cup-shaped, with 5 glands and 5 ciliate lobes; glands contiguous or somewhat apart, 2 mm in their greater diam., red-purple; female involucre 4 mm in diam., glands 1-1 1/2 mm in their greater diam.; lobes ciliate, either glabrous or pubescent on their external surface; style 3 mm long, with bifid branches, equal to, or shorter than the style column; fruit a capsule, 4-6 mm in diam., globose or somewhat angular from above, velvety, purplish, pubescent (Dyer 669a glabrous); seeds smooth, mottled.
Home