Thelocactus

Family: Cactaceae
Habitat: Texas, Mexico, and other northern areas of South America.
Cultivation: This is a fast-growing cactus, particularly susceptible to rot but, apart from that, not demanding. It wants rather accurate pots for its size. Never leave it below 4°C.
Curiosity: The name comes from the Greek “thele”, that means nipples, and refers to the many tubercles that furrow its surface (an origin of the name similar to that of the genus “mammillaria”).

KEY FEATURES

The genus Thelocactus includes 15-20 small spherical or ovoid cacti, usually solitary but sometimes forming clusters.

These plants are native to Texas and Mexico, and they grow in clay, rocky soils in arid environments, montainous areas or either grasslands and plateau.

They have been introduced in Europe in 19th century and then they became very popular among succulent enthusiasts for their beutiful, big flowers and their resistance which make them easy to cultivate.

Thelocactus, as mentioned above, are small plants 15 centimeters high, with cylindrical or globose stems, with a diameter of 20-25 centimeters, is dark green and covered by a large number of very pronounced tubercles, each with a large areola covered with whitish fluff. The tubercles are often arranged in spirals and lined in 8 to 20 ribs, which can be distinct or indistinct. They can be more or less rounded or conical, but also hexagonal.

From the areoles sprout the spines, rather long and strong. The central spines are maximum 6, more rough, vertical and erect, and can be 2 – 8 centimeters long. Their colour depend on the species and range from white, gray, golden-yellow to red-brown.

Always from the areoles, on the top of the plant, come out in late spring large diurnal flowers of various colors according to the species – red, white, yellow. They are funnel-shaped and diurnal, with a scaled ovary.

From the flowers, globose, scaly but spineless, small dry fruits develop. They are green or reddish and dehiscent. A fruit is dehiscent, in botany, when it opens after ripening to spread its seeds. There are also not dehiscent fruits, which on the contrary, never open. Seeds are small and pear-shaped.

VARIETY AND TYPES

Varieties and Types

The species of Thelocactus recognized today are less than twenty, but there are many subspecies.

Here are a few of them:

  • T. bicolor
  • T. bicolor ssp. bolaensis
  • T. bicolor ssp. commodus
  • T. bicolor ssp. heterochromus
  • T. bicolor ssp. mapimiensis
  • T. bicolor ssp. schwarzii
  • T. bicolor v. commodus
  • T. bicolor v. flavidispinus
  • T. bicolor v. mapimiensis
  • T. bicolor v. pottsii
  • T. bicolor v. schottii
  • T. bicolor v. schwarzii
  • T. bicolor v. texensis
  • T. bicolor v. tricolor
  • T. bicolor v. wagnerianus
  • T. boleanus
  • T. buekii
  • T. buekii ssp. matudae
  • T. conothelos
  • T. conothelos ssp. argenteus
  • T. conothelos ssp. aurantiacus
  • T. conothelos ssp. flavus
  • T. conothelos v. argenteus
  • T. conothelos v. aurantiacus
  • T. ehrenbergii
  • T. flavus
  • T. garciae
  • T. hastifer
  • T. heterochromus
  • T. hexaedrophorus
  • T. hexaedrophorus f. caespitosus
  • T. hexaedrophorus ssp. kvetae
  • T. hexaedrophorus ssp. lloydii
  • T. hexaedrophorus v. droegeanus
  • T. hexaedrophorus v. fossulatus
  • T. hexaedrophorus v. lloydii
  • T. hexaedrophorus v. lloydii f. maior
  • T. hexaedrophorus v. lloydii maior
  • T. lausseri
  • T. leucacanthus
  • T. leucacanthus f. krainzianus
  • T. leucacanthus ssp. schmollii
  • T. lophothele
  • T. macdowellii
  • T. matudae
  • T. mcdowellii
  • T. mirandus
  • T. multicephalus
  • T. multicephalus f. nova
  • T. nidulans
  • T. panarottoanus
  • T. paradensis
  • T. pottsii
  • T. rinconensis
  • T. rinconensis ssp. freudenbergeri
  • T. rinconensis ssp. multicephalus
  • T. rinconensis ssp. nidulans
  • T. rinconensis v. mirandus
  • T. rinconensis v. nidulans
  • T. rinconensis v. phymatothelos
  • T. sanchez-mejoradae
  • T. santaclarensis
  • T. saussieri
  • T. schwarzii
  • T. setispinus
  • T. setispinus v. orcuttii
  • T. tulensis
  • T. tulensis v. buekii
  • T. tulensis v. matudae
  • T. tulensis v. rinconadensis

TIPS FOR GROWING

Here are our cultivation tips:

  • Put your Thelocactus under direct sunlight.
  • Keep it above 4°C (39°F) and shelter it during the winter.
  • Water every 3-4 days in spring and summer, decreasing the frequency in autumn and stopping completely in winter. Make sure the soil is well dry before proceeding with the waterings.
  • In nature it prefers calcareous soils. A standard compost for cacti can also be used for cultivation.
  • Fertilize your Thelocactus twice a year, in early spring and early summer.
  • For a healthy growth it is advisable to use pots just slightly larger than the diameter of the plant. Since, however, these cacti have rapid growth, repotting will probably be necessary every year.

The most used propagation method is usually sowing. However, for cuttings, suckers may possibly be used, but in most species they are extremely rare.

Official Web Site:
www.giromagi.com

Italian Blog:
www.giromagicactus.com

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