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Bright red throat magenta-pink petals

Description: Globular usually solitary cacti up to 10 cm in diameter .
Stem: ovoidal, 8-20 cm tall, 5-12 cm wide.
Ribs: 8, distinct. Tubercles rounded. Areoles with glands.
Spines: Centrals 3, 15-75 mm long, ochre to reddish. It has been described as having only one, porrect, central spine, but with a careful observation it is possible to notice that the upper central spines are so appressed to the stem that they can be easily mistaken for radials. Therefore commodus has three central spines, as does the type species. Radials 8-18, 10-30 mm long, ochre to reddish, straight, acicular.
Flowers: 55-110 mm wide, magenta with a red throat from early spring to autumn.

Photo of conspecific taxa, varieties, forms and of plants belonging to the Thelocactus bicolor complex (This Taxon has lots of synonyms ( like many other cacti) whit several controversial varieties and subspecies and comprises a multitude of different forms, but where each form is linked to others by populations of plants with intermediate characteristics):
 

• T. bicolor var. bicolor (Frost hardiness -7°C )
• T. bicolor var. bolaensis (Frost hardiness -12°C ) Origin: Coahuilafrom Sierra Bola, up to 20 cm tall.
• T. bicolor var. commodus  It has been described as having only one, porrect, central spine, but with a careful observation it is possible to notice that the upper central spines are so appressed to the stem that they can be easily mistaken for radials.
• T. bicolor var. ellipticus is referable to bicolor.
• T. bicolor var. flavidispinus (Frost hardiness -12°C ) Texas 8cm in diameter, 5cm tall.
• T. bicolor var. heterochromus
• T. bicolor var. pottsii (Referable to bicolor var. heterochromus).
• T. bicolor var. rhodophthalmus is referable to bicolor.
• T. bicolor var. schottii (Frost hardiness -12°C) coming from the Big Bend area Texas, Chihuahua) characterized by a very long, papery upper spine.
• T. bicolor var. schwarzii 1 0° F (-12°C) Tamaulipas
• T. bicolor var.  texensis is an invalid name for a Texas form.
• T. bicolor var. tricolor (Frost hardiness -7°C ) A form with bright red spines. Plants with these characters can be found around Saltillo, Coahuila.
• T. bicolor var. zwakii,  It is not sufficiently distinct to deserve a subspecies rank.

Cultivars: Thelocactus bicolor cv. INERMIS

Cultivation: Easy to cultivate in a very gritty substrate with much drainage. Water regularly in summer, but do not overwater (very rot prone), it prefer a completely dry place during winter. An unheated greenhoouse would be perfect. It can survive low temperatures (appr. -12 C). Full sun to light shade

Reproduction: From seed, since the plant rarely produces plantlets.

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Scientific name: Thelocactus bicolor var. commodus Haas, Published in: Kakt. and. Sukk. 39: 86 (1988).

Origin: occurs from an area near Montemorelos, Tamaulipas, outside the limits of the Chihuahuan Desert.

Conservation status: Listed in CITES appendix 2.

Synonyms:

• Thelocactus bicolor ssp. commodus (Haas) Doweld
  Published in: Sukkulenty 1: 30 (1999)

Note: The maintenance at variety or subspecies of this taxon rank is not justified and now it is considered synonymous with:  Thelocactus bicolor ssp. bicolor (Galeotti ex Pfeiffer) Britton & Rose
 

All the information and photos in cactus art files are now available also in the new the Enciclopedia of Cacti. We hope you find this new site informative and useful.