Origin and Habitat: San Luis Potosi, Zacatecas, Tamaulipas, and Nuevo Leon, Mexico.
Altitude: Subspecies hexaedrophorus grows a lover altitude from 1100 to 2000 metres above sea level. (Subspecies lloydii 2200-2300).
Habitat: It grows in large numbers on gentle limestone hill slopes, plains and terraces in the Chihuahuan Desert, savanna, and grasslands, often in association with other plant species, including Mammillaria parkinsoniiSN|2309]]SN|20725]], Mammillaria aureilanataSN|20725]]SN|2309]], Ariocarpus retususSN|2079]]SN|2079]], Gymnocactus knuthianusSN|12746]]SN|12746]], Coryphantha maiz-tablasensisSN|3914]]SN|10267]], Astrophytum myriostigmaSN|1845]]SN|1845]], Echinocactus platyacanthusSN|10367]]SN|10367]] and Echinocereus blanckiiSN|7775]]SN|7478]], Coryphantha radiansSN|10267]]SN|3914]], Ferocactus latispinusSN|4259]]SN|4259]], Echinocereus pectinatusSN|8503]]SN|8503]], Echinocereus cinerascensSN|7478]]SN|7775]], Opuntia rastreraSN|8157]]SN|19989]], Opuntia lindheimeriSN|19931]]SN|19931]], Opuntia imbricataSN|19989]]SN|8157]], Myrtillocactus geometrizansSN|8050]]SN|8050]], Heliabravoa chendeSN|7732]]SN|7732]], Agave salmianaSN|27883]]SN|27883]], Yucca filifera, Jatropha spathulata and Fritillaria lanceolata.

• Thelocactus hexaedrophorus (Lem.) Britton & Rose
• Echinocactus hexaedrophorus Lem.
• Thelomastus hexaedrophorus (Lem.) Frič in Kreuz.

• Thelocactus hexaedrophorus (Lem.) Britton & Rose
• Echinocactus hexaedrophorus Lem.
• Thelomastus hexaedrophorus (Lem.) Frič in Kreuz.
• Echinocactus hexaedrophorus roseus Lem.
• Thelocactus hexaedrophorus var. decipiens (A.Berger) Pilbeam
• Echinocactus hexaedrophorus var. decipiens A.Berger
• Thelocactus hexaedrophorus var. droegeanus (Hildm. ex K.Schum.) Pilbeam
• Echinocactus droegeanus Hildm. ex K.Schum.
• Echinocactus hexaedrophorus var. droegeanus Schelle
• Thelocactus hexaedrophorus var. fossulatus (Scheidw.) Backeb.
• Echinocactus fossulatus Scheidw. in Otto & A.Dietr.
• Echinocactus hexaedrophorus var. fossulatus (Scheidw.) Salm-Dyck ex Labour.
• Echinocactus hexaedrophorus f. fossulatus (Scheidw.) Voss in Vilm.
• Thelocactus fossulatus Britton & Rose
• Thelocactus hexaedrophorus subs. franci Halda & Sladk.
• Thelocactus hexaedrophorus subs. jarmilae Halda & Chvastek
• Thelocactus hexaedrophorus subs. kvetae Chvastek & Halda
• Thelocactus hexaedrophorus var. labouretianus (K.Schum.) Pilbeam
• Echinocactus hexaedrophorus var. labouretianus K.Schum.
• Echinocactus hexaedrophorus f. labouretianus (K.Schum.) Schelle
• Echinocactus labouretianus Cels ex K.Schum.
• Thelocactus hexaedrophorus var. major (Quehl) Y.Itô
• Echinocactus hexaedrophorus var. major Quehl
• Echinocactus hexaedrophorus f. major (Quehl) Schelle
• Thelomastus hexaedrophorus major (Quehl) Frič in Kreuz.
• Thelocactus hexaedrophorus var. paradensis Pilbeam

• Thelocactus hexaedrophorus subs. lloydii (Britton & Rose) N.P.Taylor
• Thelocactus hexaedrophorus var. lloydii (Britton & Rose) Kladiwa & Fittkau
• Thelocactus lloydii Britton & Rose
• Thelocactus hexaedrophorus subs. lloydii f. major
• Thelocactus lloydii var. major

• Thelocactus hexaedrophorus var. fossulatus cv. Long spines (Japan) (Scheidw.) Backeb.
• Thelocactus hexaedrophorus subs. lloydii cv. monstruosus
• Thelocactus lloydii cv. monstruosus

Description: Thelocactus hexaedrophorusSN|10830]]SN|10830]] is a solitary and quite variable cactus with flattened stems. Many local forms are known, often formally described, that differ in stem, spine or flower morphology. Because of the large variability of the species in the whole distribution area, none of these are recognised today.
Stem:Globose or somewhat flattened above or umbilicate, glaucous, olive-green, or greyish-green eventually tinged in pink or purple, 3-7,5 cm tall , 8-15(-20) in diameter (eventually grows a little taller in cultivation), strongly tubercled and not ribbed.
Ribs: 8-13 indistinct, but generally evident in adult plants.
Tubercles: Fat, prominent, polygonal-rounded (hexagonal or pentagonal based), arranged in indefinite spirals, not flattened laterally, sometime compressed at the tip, 8-20 mm long, 13-27 mm large.
Areoles: 4-13 mm long, 12-28 mm apart, on top of the tubercles, elongated into a short groove, without nectar secreting glands.
Spines: Usually strong and variable in length depending on the clone often difficult to distinguish as centrals and radials.
Radial spines: 4-6 (6-8 on subsp. lloydii), erect to spreading, unequal, (5-)11-18(-60) mm long, pure white, ochre, reddish to brown, rigid, straight or curved, acicular to subulate and annulate.
Central spines: Almost always absent or sometime 1(-3), erect, much stouter than the radials, 15-18(-30) mm long, ochre, pinkish-grey, reddish, purplish, brow to whitish acicular to subulate.
Flowers: Silvery-white or rarely pinkish with more or less magenta midribs, 4,5-5,5(-10) in diameter, broader than long when expanded . Tube very short. Pericarpel covered with scales. Perianth-segments oblong, purplish; stigma-lobes yellowish white.
Fruit: Spherical, with scales, green magenta, 7-12 mm becoming dry at maturity dehiscing by basal pores.
Seeds: 1,5-2 mm long and 1,2-1,5 broad, with testa reticulate, divided into polygonal or square areas.

Notes: Thelocactus hexaedrophorusSN|10830]]SN|10830]] is an example of hexagonal configurations of stem-segments surface, other plant that show hexagonal tubercles comprises Matucana krahniiSN|6031]]SN|6031]] and Tephrocactus geometricusSN|14349]]SN|14349]].

Bibliography: Majoer references and further lectures
1) N. L. Britton, J. N. Rose “The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family.” Volume 4, The Carnegie Institution of Washington, Washington 1923
2) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
3) James Cullen, Sabina G. Knees, H. Suzanne Cubey "The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass" Cambridge University Press, 11/Aug/2011
4) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
5) Clive Innes, Charles Glass “Cacti” Portland House, 01/May/1991
6) Hisho Hirao “Colour Encyclopaedia of Cacti” Seibundo Shinkosha Pub. Co., Ltd 1976
7) E Haustein “Der Kosmos Kakteenfuehrer” Balogh Scientific Books, United States, 01/Dec/1998
8) Willy Cullmann, Erich Götz (Dozent Dr.), Gerhard Gröner “The encyclopedia of cacti” Timber Press, 1987

Cultivation and Propagation: This cactus is easy to cultivate and recommended for any collection that needs lots of light with ample airflow.
Growth rate: It is a small growing, but easily flowering species. It offset from the base and can fill a 25 cm pot in just a few years given the best conditions.
Soils: It likes very porous standard cactus mix soil with little organic matter (peat, humus).
Repotting: Repotting every 2-3 years. It will need a pot with sufficient depth to allow the tap root. As it is especially prone to rot under-pot in a smaller container filled with very porous compost. Use pot with good drainage.
Watering: Water regularly in summer, but do not overwater (very wet-sensitively, especially in light of its succulent root system). Its roots are easily lost in pots that stay damp for any length of time. Keep dry with ample airflow in winter. In the rest period no high atmospheric humidity!! Care must be taken with watering as they tends to become swollen and untidy in growth habit if given too much water and shade.
Fertilization: During the growing season enrich the soil using a fertilizer rich in potassium and phosphorous, but poor in nitrogen, because this chemical element doesn’t help the development of succulent plants, making them too soft and full of water.
Hardiness: Reputedly sensitive to frost , but less so if kept on the dry side prior to, and during, cold weather (hardy to -7° C for short periods). However some warmth throughout the year will increase the grower's success (minimum 5° to 8°C during rest season).
Exposition: Outside bright sun, filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Subject to sunburn if exposed to direct sun for too long. Tends to bronze in strong light, which encourages flowering and heavy wool and spine production.
Uses: It is an excellent plant for container growing. It always looks good and stays small. It look fine in a cold greenhouse and frame.
Pests & diseases: It may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests to watch for:
- Red spiders: Sensitive to red spider mite. Overhead watering is helpful in controlling mites.
- Mealy bugs: Occasionally mealy bugs they develop aerial into the new growth among the wool with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Scales: Scales are rarely a problem.
- Rot: Rot it is only a minor problem with cacti if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Reproduction: Nearly always from seed, since the plant rarely produces plantlets.