Origin and Habitat: Argentina only in an area near Tilcara.

• Gymnocalycium saglionis subs. tilcarense (Backeb.) H.Till & W.Till
• Brachycalycium tilcarense Backeb.
• Gymnocalycium saglione subs. tilcarense (Backeb.) H.Till & W.Till
• Gymnocalycium tilcarense (Backeb.) H.Till & W.Till

• Gymnocalycium saglionis (F.Cels) Britton & Rose
• Echinocactus hybogonus Salm-Dyck
• Gymnocalycium saglione Britton & Rose
• Gymnocalycium saglionis var. jujuyense Backeb.

• Gymnocalycium saglionis subs. tilcarense (Backeb.) H.Till & W.Till
• Brachycalycium tilcarense Backeb.
• Gymnocalycium saglione subs. tilcarense (Backeb.) H.Till & W.Till
• Gymnocalycium tilcarense (Backeb.) H.Till & W.Till

Description: Gymnocalycium saglionisSN|12116]]SN|12116]] subsp. tilarense differs from subspecies saglionis in having flowers with shorter floral tubes and occurring only in an area near Tilcara.
The typical Gymnocalycium saglionisSN|12116]]SN|12116]] (commonly known as the "Giant Chin Cactus") is a solitary barrel cactus, rather flattened, often very large, with long spreading and sometimes recurved spines.
Stem: Flattened globose to shortly cylindrical more or less flattened up to 30 (40) cm in diameter, 15-30 cm tall occasionally up to 90 cm tall, dull-green or blue-green.
Ribs: 10-32 according to the size of the plant, low, very broad, sometimes 4 cm. long, separated by wavy intervals, divided into large, low, rounded tubercles.
Areoles: About 2 to 4 cm apart, large, felted when young.
Spines: 8 to 10 on small plants but on old plants often 15 or more, 3-4 cm long, yellowish-brown, reddish or black becoming grey with time which contrast well against the green body at first ascending, afterwards more or less curved outward.
Central spines: 1-3 almost straight.
Radial spines: 10-15 bent against the stem.
Flowers: Broadly funnelform, white or pale pinkish, with reddish throat up to 3-4 cm long, 2-3 cm in diameter, with a very short flower’s tube.; inner perianth-segments spatulate, acute; scales of the ovary nearly orbicular, rounded, with a scarious margin. The flowers forms a crown on the plant apex and have a hard time coming through the dense mass of spines.
Blooming season: Appearing repetitively during the growing season.
Fruit: Red, globular.

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) 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
5) Curt Backeberg “Die Cactaceae: Handbuch der Kakteenkunde” Gustav Fischer Verlag, Stuttgart New York 1982–1985

Cultivation and Propagation: Gymnocalycium bruchiiSN|14835]]SN|14835]] is a summer grower species that is easy to cultivate. It is one of the most cold-tolerant South American species. It can grow outdoors and is hardy to -15° C or even less.
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: Use pot with good drainage.
Watering: Needs moderate to copious waterings in summer, but do not overwater (Rot prone), keep dry in winter.
Fertilization: Feed with a high potassium fertilizer in summer.
Hardiness: Reputedly very resistant to frost if kept on the dry side prior to, and during, cold weather (hardy to -15 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.
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: 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.
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.