Xerophyte

Description

It is a small barrel cactus that normally grows unbranched.

Spines

5 to 10 (more frequently 8) per areole, loosely projecting, grey, tan, or brown, annulate-ridged, subulate, ± flattened, glabrous, short and not hiding stem surface

Ribs

Up to 13 ribs (mostly 8), vertical to helically curving around stem, rib crests broadly rounded, uninterrupted or slightly constricted between areoles.

Stem

Pale, grey-green to bright glaucous grey-blue, flat-topped or hemispheric, spherical with age or stoutly short cylindrical, stem slowly growing up to 30 cm tall, 15-20 cm in diameter or more. The apical meristem is protected by whitish-yellow wool, which shades developing flower buds and fruits.

Areoles

Round, full of white wool when young.