Description: It is a small and very beautiful cactus completely
covered with wool and spines. Branches to form small groups or rarely
Stem: Cylindrical, 3,5-7 cm in diameter, 6-10(-15) cm tall,
epidermis dark green concealed by the dense spines.
Ribs: 21 to 27, approx 5 -7 mm wide and 2-4 mm highly, arranged
into tubercles, on which the areoles sits.
Areoles: Roundish, 2-3 mm in diameter, very close one to each
other (approx 2 mm apart), filled by white wool that persist for some
years, then naked. Annual increase 5-6 areoles per ribs.
Spines: Very dense white and copper coloured, not stinging. The
spines in the blooming areoles are often darker.
Radial spines: 40 - 50 up to 7 mm long, very fine, pure white,
lying close, radiating, interlacing with the spines of the adjacent
Central spines: 4 – 8 (of which 4 true centrals and 3-4
intermediate), up to5 mm long, Longer and stouter, spreading, copper-red
or brown. The central spines often are not present in the new apical
growth but appears later.
Flowers: Opening at the top of the stem, approx 35 mm long and 40 mm
wide, sulphur-yellow, odourless, self sterile. Tube: 12 - 15 mm long,
funnel-shaped, diameter at the base 4 mm, above 13-15 mm Ř, with
yellowish epidermis, completely covered by wool and red-brown to
dark-brown bristles up to 10 mm long. Stamens 7-9 mm long,
golden-yellow. Petals: lanceolate to narrowly lanceolated, up to 4 mm
wide and 21 mm long, inside and outside sulphur-yellow, shining. Stylus:
17 mm long, 1.2-1.5 mm Ř, dark-carmine, with 11 (12) stigma lobes up to
3.5 mm long. Blooming season:
flowers pen on the late morning and close at night.
Fruit: Small 6-7 mm broad and long, fleshy, pinkish, cover with
white cotton wool, drying yellowish, irregularly opening with the
releasing of part of the seeds to the ground (but some of the seeds
remain on the plant). Each fruit contains approx 80 seeds.
Seed: Helmet-shaped, black. Length 0.65 mm, width 0.5 mm, height of
0.4 mm, Hilum oval, curved, light brown. Testa convex to hemispherical,
bordered with 5 to 7 adjoining cells, 0.03 - 0.07 mm Ř. Microphylar hole
0.13-0.1 mm Ř and 0.04 mm.