Xerophyte

Central Spines

4 to 8, elongated, stiff, terete, round, angled, or somewhat flattened in cross section, usually less than 8 cm long, but sometimes 15 cm long, curved backward to hooked at apex, sometimes twisted.

Seeds

Ovate, about 1-1,5 mm, shiny black, pitted , and with a basal-lateral hilum that is marked by a sharp, narrow hilum-micropylar rim.

Roots

Diffuse

Flowers

Near apical in a ring, funnelform with well-developed floral tubes, (6-)7-8(-10) cm long, 6-8 cm in diameter, glossy, mostly yellow with a pale green throat, in some forms scarlet within. Pericarpel surface with 10-40 small, triangular scales with greenish-yellow, fringed margins. Filaments yellow to orange-yellow, anthers and pollen yellow. Stigma stigma yellow longer than stamens, with 8-14 lobes curved and twisted 4,5-6 mm long. The flowers are scented.

Spines

Somewhat variable in number, diameter, and position, mostly yellowish, especially near the stem apex, sometime indistinctly annulate and often variegated, turning grey as they ages. The areoles of immature plants have fewer and shorter central and radial spines than is typical in adult areoles.

Ribs

10-13, sometimes 17, rounded but not compressed at the crest, ofyten poorly defined, large, 2,5-5 cm high and thick and divided into rounded tubercles with areoles on tops.

Stem

Hemispherical or spherical, becoming oblong or cylindrical, dark green to grey-green, up to 60 cm high (exceptionally near 90 cm high) and 5-30 cm in diameter partially obscured, mostly by interlacing radial spines.

Fruits

Egg shaped, 2 to 5 cm. long, 2,5-3 cm in diameter fleshy, greenish yellow, green to pinkish red, dark brown to drab-colored (not red) usually with a persistent floral remnant, and with 50-40 widely spaced scales on the surface. The fruit of this species is unlike that of most other species of the genus; the skin is thin and the white pulp, is juicy, sweet and edible. Mature fruits sometime splits open by the the rupturing of the fruits near the apex and the extrude the seeds in a liquid, but more the fruits are indehiscent and dries on the plant and do not dehisce via a basal pore. The fruits persist through the summer and autumn and mature in winter.

Habit

It is a small to medium sized barrel cactus, solitary, or double or triple branched after injury.

Blooming Season

Late summer to autumn, flowers open midday, partially close at night, and reopen again for several days. Plants starts blooming when stems reach 15 cm high or less.

Radial Spines

About 8-14(-20), acicular, terete, somewhat compressed or angled, relatively stout and stiff or somewhat thin and flexible, or even sinuate, 5 to 8 cm long, upper ascending, lower descending, laterals appressed.

Areoles

Large circular to elliptic, 1 to 3 cm apart with felted grooves running inward and upward with white, yellowish or grey wool in younger areoles. Between the flower and the spines in each areole there are some elongated glands, 2 to 4 mm long, these at first are soft, but in age become hard and spine like.