Xerophyte

Habit

Either solitary or forming massive clumps consisting of many stems.

Central Spines

Single, straight, pointing outward, tapering, nearly bristle-like 33–38 mm long.

Roots

It has a big taproot which is considerably longer than the stem and serves for storing water. The main root may be several times the length of the above-ground body.

Flowers

Few at a time, opening widely, diurnal closing at night, fragrant, protracting the period of opening many days, funnel-shaped, 3–3,5 cm long.

Spines

Very variable in colouration, black, brown or grey.

Ribs

12–13(-16) sharp, to obtuse, slightly rounded and barely dissolved in tubercles. Usually straight but occasionally spirally arranged.

Stem

Globose, to elongate globose up to 12 cm across, grey-green with a greyish bloom and crowned by a dense mass of silky dull-yellow or brownish wool, particularly at flowering time. The grey colouration is a waxy coating presumably produced to prevent desiccation in it's extremely dry environment. In cultivation the waxy bloom is often not produced, revealing a green epidermis.

Radial Spines

5-7 more slender, slightly backward curved, 10–12 mm long.

Fruits

Green to pink coloured, with a few scales.

Areoles

3-10 mm in diameter, almost round, approximate, the adjoining ones usually touching. Young areoles filled with soft yellowish to orange-brownish felted wool, turning grey or blackish, later almost glabrous.