Origin and Habitat: It is known only from the slopes of Arteaga Canyon just south of Saltillo, Coahuila. Mexico.
Altitude: Around 1900 metres above sea level.
Habitat: Chihuahuan Desert. Often found growing together with Neolloydia conoideaSN|10089]]SN|10089]].

• Thelocactus rinconensis subs. phymatothelos (Poselg.) Glass
• Echinocactus phymatothelos Poselg.
• Thelocactus rinconensis var. phymatothele (Poselg.) Glass & R.A.Foster

• Thelocactus rinconensis (Poselg.) Britton & Rose
• Echinocactus rinconensis Poselg.
• Thelocactus rinconensis subs. freudenbergeri (R.Haas) Mosco & Zanov.
• Thelocactus rinconensis var. freudenbergeri R.Haas
• Thelocactus rinconensis var. lophothele hort.
• Echinocactus lophothele Salm-Dyck
• Thelocactus lophothele (Salm-Dyck) Britton & Rose
• Thelocactus rinconensis subs. nidulans (Quehl) Glass
• Echinocactus nidulans Quehl
• Thelocactus lophothele var. nidulans (Quehl) Kladiwa & Fittkau
• Thelocactus nidulans (Quehl) Britton & Rose
• Thelocactus rinconensis var. nidulans (Quehl) Glass & R.A.Foster
• Thelocactus rinconensis subs. palomaensis Pavlíček & Zatloukal
• Thelocactus lophothele subs. palomaensis Matusz.
• Thelocactus palomaensis
• Thelocactus rinconensis subs. phymatothelos (Poselg.) Glass
• Echinocactus phymatothelos Poselg.
• Thelocactus rinconensis var. phymatothele (Poselg.) Glass & R.A.Foster

• Thelocactus rinconensis subs. multicephalus (Halda & Panar.) Lüthy
• Thelocactus multicephalus Halda & Panar.

Description: Thelocactus rinconensisSN|10887]]SN|10887]] subs. phymatothelos, better known as Thelocactus phymatothelos, can be distinguished from other forms of the Thelocactus rinconensis complex because the stem is always strongly depressed and glaucous, the spines are few, shorter and slightly curved, and the flowers are more or less clear pink.
Habit: Usually solitary or very slow to offset, develops a squat and highly ribbed stem with a flattened top.
Stem: Spherical with a compressed top, 9-15(-20) cm across, ap to 10 cm tall, chalky-grey, silvery-grey, glaucous sometimes tinged with purple.
Ribs: Mostly obscured by tubercles that are very prominent angled but more rounded and compressed than those of the main species Thelocactus rinconensisSN|10887]]SN|10887]]. Tubercles up to 1,5 cm hight.
Areoles: Round to elongate, mostly more than 2 cm apart and without nectaries.
Spines: Usually short but variable in length, depending on the clone, dark, usually black-brown , pale at apex, but also grey, brown or yellow, with a distinctive silvery appearance, and sometimes shredding. Spines in old age shiny grey-white.
Central spines: Most often 1-2 (rarely more) slightly curved, sometimes scaly with age, usually very short or occasionally up to 6 cm long.
Radial Spines: up to 5 (usually only1-2) similar to the centrals, erect to radiating, slightly curved shorter than the centrals.
Flowers: 3-5 cm long, 2,7-3 cm in diameter, white to pinkish with a pink midstripe. Tube short, pericarpels covered
with scales. The plants usually fail to flower until they are 5-9 years old.
Fruit: Spherical ta oblong with scales, 7-9 mm in diameter, greenish or yellowish, slightly fleshy when ripe, opening by basal pore.

Notes: Thelocactus phymatothelos is now considered a synonym of Thelocactus rinconensisSN|10899]]SN|10887]], along with Thelocactus lophotheleSN|10887]]SN|10899]], Thelocactus nidulans, and others. It is not sufficiently distinct to deserve its own formal status.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) 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
3) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
4) Urs Eggli, Leonard E. Newton: “Etymological Dictionary of Succulent Plant Names” Springer, Berlin/Heidelberg 2010
5) Philip Perl “Cacti and succulents” 1978
6) N. L. Britton, J. N. Rose: “The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family.” Volume III, The Carnegie Institution of Washington, Washington 1922
7) Hans Hecht “BLV-Handbuch der Kakteen” BLV-Verlagsgesellschaft, 1982
8) E Haustein “Der Kosmos Kakteenfuehrer (the Kosmos Cactus Guide)” Balogh Scientific Books 01 December 1998
9) Paul Carpenter Standley “Trees and shrubs of Mexico, Parti 1-3” Govt. Print. Off., 1926
10) Edgar Lamb, Brian Lamb “The Illustrated Reference on Cacti & Other Succulents, Volume 5” Blandford Press, 1978
11) Clive Innes “Complete Handbook of Cacti and Succulents” Van Nostrand Reinhold Company, 01/Dec/1981
12) Walther Haage “Cacti and succulents: a practical handbook” Dutton, 1963
13) A. J. van Laren, Scott Edson Haselton “Cactus” Abbey San Encino Press, 1935
14) Gordon D. Rowley “The illustrated encyclopedia of succulents” Crown Publishers, 01/Aug/1978
15) Hans Hecht “Cacti & Succulents” Sterling Publishing Company Incorporated, 1994
16) Roger Spencer "Horticultural Flora of South-eastern Australia: The Identification of Garden and Cultivated Plants. Flowering plants : Dicotyledons, Volume 2, Parte 1” UNSW Press, 1997
17) John Pilbeam “Cacti for the Connoisseur: A Guide for Growers & Collectors” Timber Press, 01/Jul/1987

Cultivation and Propagation: Easy to cultivate. Water moderately from Spring to Autumn. In Winter, keep dry.
Sun Exposure: Full sun to light shade
Reproduction: Nearly always from seed, since the plant rarely produces plantlets.