Conservation status: Listed in
CITES Appendix II
Thelocactus macdowelii (Rebut ex
Quehl) C. Glass, Published in: Cact. Suc. Mex. 14: 4
Origin: Mexico (Nuevo León, Coahuila)
Habitat: Occurring in
matorral xerofilo on limestone hills. This plant is quite rare and
only known from a few localities in the wild.
- Echinocactus macdowellii Rebut ex
Quehl ('Mc. Dowellii'),
in: Monatsschr. Kakt.-Kunde 4: 133-134 (1894).
- Echinomastus macdowellii Br. &
R., Cact. 3: 151 (1922)
- Neolloydia macdowellii H. E.
Moore, Badleya 19: 166 (1975)
- Thelocactus conothelos var. macdowellii
Glass & Foster ('mcdowellii'), Cact. Succ. J. (US) 49: 220
- Thelocactus macdowellii (Rebut ex
Quehl) W.T. Marshall
- Thelocactus conothelos ssp. macdowelli
var. sniceri Halda & Sladkovsky, Acta Mus. Richnov. Sect.
natur. 7: 38 (2000).
Description: Solitary cactus that can in time
grow several heads.
Stem: Light green, up to 10 cm tall and 10 cm wide.
Ribs: Indistinct divided in conical tubercles.
Radial spines: Glassy white acicular, usually between 15 and 25.
Central spines: 2-4 white or light yellow.
Flowers: Funnel-shaped, pink (or magenta) with a yellow centre
and about 6 cm wide Not self-fertile.
Blooming season: Usually flowers only once in mid to late winter
(or early spring) but sometimes it can do a 2nd round like it happens
with all seasonal bloomers once in a while.
Fruit: The Green and shiny. Hairless and spineless.
Cultivation: It is a summer
grower species and does not require any special treatment. Water
regularly from Spring to Autumn, but do not overwater. Requires full sun
or light shade and careful watering to keep plant compact with strong
spines. It will stand as much sun as you can give it, as long as there
is good air circulation.
Needs good drainage and very porous potting mix, it can become too
elongated if compost is too rich.
It will flower much better if it has a cool resting period during the
winter, when little or not water is given. Frost Tolerance: Hardy to -7°
Propagation: From seed (usually) or cuttings.