Origin and Habitat: Sierra Ambato, Catamarca, Argentina.
Altitude range: It occurs at elevations of 130-1800 metres above sea level.
Habitat and Ecology: Gymnocalycium oenanthemumSN|28334]]SN|28334]] subs. carminanthum grows in high altitude grasslands on rich mineral soil among the grasses or in rock crevices. The major threat is intentional fires in the grasslands. The species is threatened in part of its range by collectors.

• Gymnocalycium oenanthemum subs. carminanthum (Borth & Koop) H.Till
• Gymnocalycium carminanthum Borth & Koop

• Gymnocalycium oenanthemum Backeb.
• Gymnocalycium oenanthemum subs. carminanthum (Borth & Koop) H.Till
• Gymnocalycium carminanthum Borth & Koop
• Gymnocalycium tillianum Rausch
• Gymnocalycium tillianum subs. montanum (Slaba) F.Berger
• Gymnocalycium carminanthum var. montanum Slaba

Description: Gymnocalycium oenanthemumSN|28334]]SN|28334]] subs. carminanthum best known in cultivation as Gymnocalycium carminanthumSN|28336]]SN|28336]] is a solitary stemmed species, of modest size, with stout spines slightly curved inward which is particularly attractive for its beautiful bright carmine-red flowers. It grows at around 1300 to 1800 m asl, but apart the colouration of flowers it is the same as Gymnocalycium oenanthemumSN|28334]]SN|28334]] and not readily distinguishable.
Stem: flattened globose, dull grey-green to to bluish green, 6-8(-10) cm high and 7-9(-12) cm in diameter.
Ribs: (6-)11-13, broad. obtuse, sharply angled.
Central spine: Usually absent, sometimes one erect.
Radial spines: Usually 5(-7), reddish grey with dark tips, stout, straight to slightly curved inward, to 1.5-2 cm long, pinkish at first, later grey.
Flowers: Wine red, carmine-red or deep salmon-pink, shiny, to 5 cm long and 4-4.5 cm in diameter lasting approx 4 days..
Fruits: Ovoid, green.
Seeds: 0.8 mm in diameter, dark brown to black, tuberculate, with small pale hilum.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
3) Roberto Kiesling, Omar E. Ferrari “Cien cactus argentinos” Editorial Albatros, 2005
4) 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
5) Hans Krainz “Die Kakteen: eine Gesamtdarstellung der eingeführten Arten nebst Anzucht- und Pflege-Anweisung” Franckh'sche Verlagshandlung” Lfg. 59. 1974
6) Demaio, P., Perea, M. & Trevisson, M. 2013. Gymnocalycium oenanthemum. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 08 August 2014.
7) Blätter für Kakteenforschung 1934. Nummer 9, S. [2], 1934, Genus 74, Species 4.
8) Zuloaga, F. O., O. N. Morrone, M. J. Belgrano, C. Marticorena & E. Marchesi. (eds.) 2008. Monogr. Syst. Bot. Missouri Bot. Gard. 107: 3 Vols., 3348 p.

Cultivation and Propagation: Gymnocalycium oenanthemumSN|28334]]SN|28334]] subs. carminanthum is a summer grower species that is easy to cultivate.
Growth rate: It is a relatively rapidly growing and easily flowering species that will make clumps given the best conditions.
Soils: It likes very porous standard cactus mix soil. Prefer a low pH compost, avoid substrata rich in limestone; otherwise growth will stop altogether.
Repotting: This plant needs plenty of space for its roots, repotting should be done every other year or when the it has outgrown its pot. Use pot with good drainage.
Watering: Needs moderate to copious waterings in summer, but do not overwater (Rot prone), keep dry in winter at a minimum temperature of 0°C.
Fertilization: Feed with a high potassium fertilizer in summer.
Hardiness: Reputedly resistant to frost if kept on the dry side prior to, and during, cold weather (hardy to -5 C ° C, or less for short periods).
Exposition: The plant tolerates extremely bright situations but enjoys filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Tends to bronze in strong light, which encourages flowering and heavy spine production, but is likely to suffer from sun scorch or stunted growth if over exposed to direct sunlight during the hottest part of the day in summer.
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 or outdoor in a rockery.
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: Red spiders may be effectively rubbed up by watering the plants from above.
- Mealy bugs: Mealy bugs occasionally 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: This species is particularly easy and accommodating, seldom suffer of cryptogamic diseases. Rot it is only a minor problem with gymnocalyciums if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Propagation: Division, direct sow after last frost. Seeds germinate in 7-14 days at 21-27° C in spring, remove gradually the glass cover as soon the plants will be well rooted (ca 1-2 weeks) and keep ventilated, no full sun for young plants! To make a cutting twist off a branch and permit it to dry out a couple of weeks, lay it on the soil and insert the stem end partially into the soil. Try to keep the cutting somewhat upright so that the roots are able to grow downward.