Xerophyte

Central Spines

One, thicker, upward pointing, round in cross-section, 3,5-5 cm long and about 1,5 mm in diameter.

Seeds

2 x 1,5 mm, black, shiny, surface with minuscule bumps.

Roots

Napiform often forked, yellowish-brown, neck slightly constricted. Lateral roots fibrous, growing mostly from the upper part of the central root.

Tubercles

Rounded, slight depressed in correspondence to each areole.

Flowers

1 to 2 at a time, diurnal closing at night, fragrant, protracting the period of opening many days, funnel-shaped, 40-46 mm long and 30 mm in diameter growing from the centre of the grey wool at the apex. The perianth segments are 11-19 mm long and 5-7 mm wide, blunt and pale-yellow with a outer reddish mid-stripe. Pericarpel greyish, hairy. Style 18 mm long, yellow. Stigma yellow, 12 to 15 lobes, 3 mm to 6 mm long. Stamens 5 mm to 15 mm long, yellow.

Blooming Season

Spring ( September onward in habitat)

Ribs

There are 10 to 20 strongly tuberculate especially in young specimens

Stem

Up to 50 cm tall and 23 cm in diameter, spherical or elongated with a slightly tapered apex, usually solitary or rarely forming multi-headed plants. Epidermis and ribs not obscured by spines, homogeneous pistachio green, without farinose coating, and crowned by a dense mass of white wool, particularly at flowering time. Apex up to 6 cm in diameter, spineless and depressed.

Radial Spines

5-6 stout, fairly slender, straight and stiff, 10-30 mm long and o,6-0,8 mm in diameter, evenly spreading, erected with a narrow lateral spine angle, round in cross-section, dark chocolate-brown quickly ageing into pale grey.

Fruits

Round to elongate, with up to 180 seeds.

Areoles

Large, broad, almost round about 8 mm in diameter, approximate, the adjoining ones usually touching. Young areoles filled with soft dull white felted wool quickly ageing toalmost dark grey and often sunken into the ribs.