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Only the leaf-like rosette of tubercles is visible on this plant.
Ariocarpus retusus is the largest species of the genus.
It is also
one of the easiest and fastest to grow.
It might still take 6-10 years, to
go from seeds to flowering size.
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Description: Solitary, slow growing
geophyte cactus with tubercles slightly projecting above ground
level. The flat tuberous body is below the soil.
Stem: Grey, or blue-green, flattened, globose, rounded on top,
3-12cm high, 10-25cm in diameter.
Tubercles: Leaflike, divergent, erect, basally compressed, usually
becoming attenuate at the apices, convex or nearly flattened
adaxially and often with shallow adaxial undulations or wrinkling,
not fissured, 1.5-4cm long, 1-3.5cm wide, nearly as
wide as long;
Areoles: at the tips of the tubercles, rounded, 1-5mm in
diameter.
Flowers: Diurnal 4-5cm in diameter., 2-4 2cm long; white to pink
(or magenta), occasionally with reddish midribs,
Root: Tap root
Flowering time: October
Fruit: white, green, or rarely pinkish, 10-25mm long, 3-10mm in
diameter.
Ariocarpus retusus is an extremely variable species
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Ariocarpus retusus SB240 Matehuala |
A. retusus LH453 Las Tablas, SLP. MX |
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A. retusus
SB68 Coronel, SLP, Mexico.
Cultivation: This species is slow growing but
certainly not as slow as some other types of cacti, it is of easy
culture in a well drained, non-organic, free-draining soil compost, with
ample water during the growing season. Use of a weak low-nitrogen
fertilizer during the growing season can encourage growth. The main
threat to their development is root rot. Ariocarpus should be kept dry
whenever there is a threat of cold. The appearance of Ariocarpus can
benefit greatly by watering the plants from the bottom. This practice
will help to keep the “wool” on the top of the plant from becoming
matted or discoloured. Need light shade to full sun. Frost Tolerance:
Hardy to -10° C
Propagation: It is probably the easiest species of the genus to
raise from seed, but will generally take about 6-10 years to reach
flowering size, occasionally grafted.
The pointed tubercles are usually smooth with areoles.
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A. retusus
LH453 Las Tablas, SLP. |
A. retusus
SB68 Coronel, SLP. |
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A. retusus
SB240 Matehuala, SLP |
A. retusus forma Matehuala (Köhres seeds)
This population has dark green long and stiff tubercles. |
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Family:
Cactaceae (Cactus
Family)
Scientific name: Ariocarpus retusus
Scheidweiler, (1838)
Pubblished in: Bull. Acad. Sci. Brux. 5: 492
Conservation status: Listed in
CITES Appendix I
Synonyms:
- Anhalonium prismaticum Lemaire 1839
= Mammillaria prismatica
- Ariocarpus elongatus Lee 1937Scientific
= Anhalonium elongatum Salm-Dyck 1850
- Ariocarpus pulvilligeris
- Anhalonium areolosum,
Common name: Living Rock, Seven Stars
Origin: widely distributed from north of Saltillo,
Coahuila southwards to San Luis Potosi, SLP, Also found occur in
Tamaulipas , Zacatecas and Nuevo Leon.
Habitat: High Chihuahuan desert at altitudes of between
1300 and 2000 metres, on calcareous hillsides and occasionally gypsum
plains. At lower altitudes (200 - 800m) of the Sierra Madre Oriental it
is replaced by A. retusus ssp. trigonus.
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Ariocarpus retusus is an extremely
variable species,. Tubercle size and shape vary widely, a terminal
areole is sometimes present at the tip. The vast amount of phenotypic
variation in the species has led to the erection of several variants:
- A. retusus ssp. retusus: widespread, flowers are cream or
white, occasionally with reddish midveins.
- A. retusus ssp. trigonus: somewhat less widespread
with long sharp tubercles twice as long as wide. The flowers are
yellow (usually), white to pinkish white.
- A. retusus v. furfuraceus: applied to plants with
equilaterally triangular shaped tubercles
- A. retusus ‘furfuraceus’ var. rostratus refers to
plants with a more tapered apex to the tubercle.
- A. retusus v. scapharostroides plants from the Villa
Juarez region of SLP, it is characterized by erect angular tubercles,
superficially reminiscent of A. scapharostrus.
- A. retusus confusus nomina nuda
- A. retusus subsp. jarmilae nomina nuda
- A. retusus subsp. horaceki nomina nuda
- A. retusus var. pectinatus nomina nuda
- A. retusus subsp. panarottoi nomina nuda
- A retusus var. minimus is a nomina nuda which has
recently been applied to plants from Echido Nuncio,in San Luis Potosi.
- A. retusus f. major applied to selected cultivated
plants with very broad shaped tubercles (“Tama-botan” in
Japan).
A. retusus LH453 Las Tablas, SLP. MX
Photo and © copyright by
Andrea B. (Bologna, Italy)
http://www.cactusfriends.com/Andrea/index.html
Photo of
conspecific taxa, varieties, forms and cultivars of Ariocarpus
retusus.
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