Xerophyte

Habit

Usually solitary, forms white columns with dark contrasting spination.

Central Spines

1-3 sub-erected, strong, more than 2 cm long, black.

Seeds

Shining-black.

Roots

Not napiform.

Flowers

Diurnal closing at night, protracting the period of opening many days and arising on the crown, often several at a time, funnel form, small (2-3 cm long), yellow, scentless.

Ribs

27-47, depressed, obtuse and tuberculated, approx 1 cm wide, 5-7 mm tall. Inter-ribs suture wavy.

Stem

Variable 50-75 cm tall, 10-20 cm in diameter, epidermis covered with a thick stratum of ashy-white pruine. Apex flattened with abundant dark-grey wool and without spines.

Radial Spines

4-5 thin and arching, 5-8 mm long. Normally not present in adult specimen.

Fruits

Deeply concealed within the apical wool, round or egg-shaped, pale green reddening toward the apex, almost naked with only few (3-4 mm long) scales. Almost completely dry at maturity.

Areoles

Small (diameter 2-3 mm), oblong, with yellow-orange wool (later becoming grey) recessed within the lower part of tubercle, 4-8 mm apart.