Bright red throat magenta-pink petals
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
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):
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.
- T. bicolor var. rhodophthalmus is referable to
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.
Thelocactus bicolor cv. INERMIS
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.
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
Conservation status: Listed in
CITES appendix 2.
- Thelocactus bicolor ssp. commodus
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
The beautiful flowers are freely produced from
early spring to autumn.