Xerophyte

Habit

Simple but occasionally clustering.

Central Spines

1-4, stouter and longer than the radials, somewhat spreading or ascending, acicular, nearly straight or slightly recurved, ochre, red, reddish-white or dark blackish-brown becoming grey with age and often shedding, up to (1-)1,5-5(9) cm long.

Seeds

1,5-2,1 x 1,2-1,5 mm, testa cells conical pointed with a smooth surface.

Description

Thelocactus conothelosSN|15121]]SN|15121]] is a nice solitary cylindrical cactus with large bubble tubercles and pink flowers. It is one of the cactuses that blooms early. Like many cactus forms of dry, hot region of Mexico, plants are strongly variable. Thelocactus conothelosSN|15121]]SN|15121]] has received many unnecessary infraspecific epithets, but the only acceptable distinctions are, the type and subsp. argenteus with dense silvery spines and subsp. aurantiacus with orange flowers.

Flowers

3-5 cm long, (3-)4-5(-6) cm in diameter, tube well-developed, narrow, pericarpels naked below but with heavy scales above. Flowers are typically magenta, though there is a population near Matehuala, where white and magenta flowered plants grow together (but also yellow to orange-yellow or red).

Ribs

Not evident and replaced by upward pointing spiralled tubercles, the lower tubercles, conical, delta shaped to elliptical (8-)12-20(-24) mm long and 4-18 mm broad.

Stem

Spherical, elongated or somewhat cylindrical, 6-25-(45) cm tall and 7-17 cm across, yellowish green, greyish green to pale green.

Radial Spines

(7-)14-16(-23) needle-like, usually white or to greyish brown (5-)8-12(-20) mm long spreading.

Fruits

Spherical-oblong dry at maturity, 10-14 mm long, 6-9 mm in diameter, dehiscing by basal pores, scaly.

Areoles

Areoles with short furrows, with or (usually) without nectar-secreting glands, upper areoles oblique, white tomentose, typically 1-3 cm apart.