Xerophyte

Central Spines

1 (rarely 4) , somewhat longer than radials, straight or curved (subsp. clavata) or hooked (subsp. stipitata).

Tubercles

In rows of 5-8, and 13, conical, grooved above, the axils when young bearing short white wool; glands in the groove.one to several, large, red.

Flowers

Small for the genus, about 20-30 m in diameter (subsp. clavata) or 35-40 mm in diameter (subsp. stipitata); outer perianth-segments linear, acute, entire, with broad brownish midrib; inner perianth-segments linear, entire, narrow, creamy white; stamens pinkish, much shorter than the perianth-segments; style pinkish; stigma-lobes 5 or 6, short, greenish.

Stem

Simple, elongated to club shaped, cylindrical, 10 to 15 cm tall, dark bluish green.

Radial Spines

6 to 12, with reddish or black tips.