# Gymnocalycium

Gymnocalycium, commonly called chin cactus, is a genus of about 70 South American species of cactus. The genus name Gymnocalycium (from Greek, "naked calyx") refers to the flower buds bearing no hair or spines. In a 2023 classification of the tribe Cereeae, it was placed as the only genus in the subtribe Gymnocalyciinae, having formerly been placed in the subtribe Rebutiinae.

## Description

The species of the genus Gymnocalycium are low-growing, usually solitary or sometimes small cushion-forming plants with globose, depressed-globular to short-cylindrical stems. The 4 to 15 (rarely more) ribs are usually broadly rounded, often sinuous, occasionally warty, and often have a "chin" just below the areoles. The thorns are very variable.
The diurnal, funnel- or bell-shaped flowers appear at or near the apex. They are white or pink, sometimes yellow or bright red. The flower cup and the corolla are covered with a few large, broad and obtuse scales that have membranous edges. The areoles are bare. The perianth is usually spread.
The stamens form two circles. The first surrounds the nectar chamber, the second is attached near the opening of the corolla. The oblong to spherical fruits are dry or fleshy and spring up in various ways. A permanent flower residue adheres to them. The seeds are very variable. Their color ranges from brown to black, the size from quite small to relatively very large.
In cultivation they are popular for their easy flowering habits, and the flowers are generally brightly colored.

## Species

Species of the genus Gymnocalycium according to Plants of the World Online as of August 2023:
| Scientific name | Distribution |
| Gymnocalycium affine Řepka | Argentina (Córdoba) |
| Gymnocalycium alboareolatum Rausch | Argentina (La Rioja) |
| Gymnocalycium alenae Kulhánek | Argentina (Córdoba) |
| Gymnocalycium amerhauseri H.Till | Argentina (Córdoba) |
| Gymnocalycium andreae (Boed.) Backeb. & F.M.Knuth | Argentina (Córdoba) |
| Gymnocalycium angelae Mereg. | Argentina (Corrientes) |
| Gymnocalycium anisitsii (K.Schum.) Britton & Rose | Bolivia to Paraguay |
| Gymnocalycium × applanatum Řepka & Frélich (G. capillense × G. ochoterenae) | Argentina (Córdoba) |
| Gymnocalycium baldianum (Speg.) Speg. | Argentina. |
| Gymnocalycium basiatrum F.Berger, Amerh. & Sedlmeier | Argentina (La Rioja) |
| Gymnocalycium bayrianum Till ex H.Till | Argentina (Salta, Tucumán) |
| Gymnocalycium berchtii Neuhuber | Argentina (San Luis) |
| Gymnocalycium bodenbenderianum (Hosseus ex A.Berger) A.Berger | Argentina (to NW. Córdoba) |
| Gymnocalycium bruchii (Speg.) Hosseus | Argentina (San Luis, Córdoba) |
| Gymnocalycium cabreraense Schädlich, Bercht & Melojer | Paraguay |
| Gymnocalycium calochlorum (Boed.) Y.Itô | Argentina (Córdoba) |
| Gymnocalycium campestre Řepka | Argentina (Córdoba) |
| Gymnocalycium capillense (Schick) Hosseus | Argentina (Córdoba, San Luis) |
| Gymnocalycium castellanosii Backeb. | Argentina (La Rioja, San Luis) |
| Gymnocalycium chacoense Amerh. | Bolivia (Santa Cruz) |
| Gymnocalycium chiquitanum Cárdenas | Bolivia. |
| Gymnocalycium denudatum (Link & Otto) Pfeiff. ex Mittler | S. Brazil to Argentina (Misiones, Corrientes) |
| Gymnocalycium erinaceum J.G.Lamb. | Argentina (Córdoba) |
| Gymnocalycium esperanzae Řepka & Kulhánek | Argentina (La Rioja) |
| Gymnocalycium eurypleurum F.Ritter | Paraguay |
| Gymnocalycium gibbosum (Haw.) Pfeiff. ex Mittler | Argentina. |
| Gymnocalycium glaucum F.Ritter | Argentina. |
| Gymnocalycium horstii Buining | Brazil (Rio Grande do Sul). |
| Gymnocalycium hossei (F.Haage) A.Berger | Argentina |
| Gymnocalycium kieslingii O.Ferrari | Argentina (La Rioja, Santiago del Estero). |
| Gymnocalycium kroenleinii R.Kiesling, Rausch & O.Ferrari | Argentina (La Rioja). |
| Gymnocalycium kuehhasii Neuhuber & R.Sperling | Argentina (Córdoba). |
| Gymnocalycium kulhanekii Papsch | Argentina (Córdoba) |
| Gymnocalycium marekiorum Milt | Bolivia (Santa Cruz) |
| Gymnocalycium marsoneri Frič ex Y.Itô | Argentina (to Chaco) |
| Gymnocalycium mendozaense C.A.L.Bercht & Schädlich | Paraguay. |
| Gymnocalycium mesopotamicum R.Kiesling | Argentina (Corrientes) |
| Gymnocalycium mihanovichii (Frič & Gürke) Britton & Rose | Paraguay to Argentina (Chaco, Formosa) |
| Gymnocalycium × momo V.Gapon & Schelkun. (G. monvillei × G. mostii.) | Argentina (Córdoba) |
| Gymnocalycium monvillei (Lem.) Pfeiff. ex Britton & Rose | Argentina (to Córdoba) |
| Gymnocalycium mostii (Gürke) Britton & Rose | Argentina (Córdoba) |
| Gymnocalycium neuhuberi H.Till & W.Till | Argentina (San Luis) |
| Gymnocalycium nigriareolatum Backeb. | Argentina (Catamarca, La Rioja) |
| Gymnocalycium ochoterenae Backeb. | Argentina (San Luis, Córdoba) |
| Gymnocalycium oenanthemum Backeb. | Argentina (Catamarca) |
| Gymnocalycium paediophylum Schütz | Paraguay. |
| Gymnocalycium paraguayense (K.Schum.) Hosseus | Paraguay. |
| Gymnocalycium pflanzii (Vaupel) Werderm. | Bolivia to Paraguay. |
| Gymnocalycium pinalii Mereg. & Kulhánek | Argentina (Córdoba) |
| Gymnocalycium ponomarevae V.Gapon & Neuhuber | Argentina (Catamarca) |
| Gymnocalycium quehlianum (F.Haage ex H.Quehl) Vaupel ex Hosseus | Argentina (Córdoba). |
| Gymnocalycium ragonesei A.Cast. | Argentina (Catamarca, Córdoba) |
| Gymnocalycium reductum (Link) Pfeiff. ex Mittler | Argentina (Buenos Aires) |
| Gymnocalycium rhodantherum (Boed.) H.Till | Argentina (Salta, La Rioja, San Juan) |
| Gymnocalycium ritterianum Rausch | Argentina (La Rioja). |
| Gymnocalycium robustum R.Kiesling, O.Ferrari & Metzing | Argentina (Córdoba: near Quilino) |
| Gymnocalycium saglionis (Cels) Britton & Rose | Argentina |
| Gymnocalycium sanluisense Neuhuber | Argentina (San Luis). |
| Gymnocalycium schickendantzii (F.A.C.Weber) Britton & Rose | Argentina (San Luis). |
| Gymnocalycium schroederianum Osten | Argentina to Uruguay. |
| Gymnocalycium spegazzinii Britton & Rose | Argentina. |
| Gymnocalycium stenopleurum F.Ritter | SE. Bolivia to N. Paraguay. |
| Gymnocalycium striglianum Jeggle ex H.Till | Argentina (Mendoza, San Luis) |
| Gymnocalycium taningaense Piltz | Argentina (San Luis, Córdoba) |
| Gymnocalycium uebelmannianum Rausch | Argentina (La Rioja) |
| Gymnocalycium uruguayense (Arechav.) Britton & Rose | S. Brazil to Uruguay |
| Gymnocalycium victorii Neuhuber | Argentina (San Luis) |
| Gymnocalycium volskyi V.Gapon, Ponomareva, Protopopov, Schelkun. & Zaitseva | Uruguay |

## Distribution

Their main area of distribution is Argentina, part of Uruguay, Paraguay, Bolivia and part of Brazil.

## Gallery

* Gymnocalycium species from Liberec botanical garden
* Gymnocalycium species from Liberec botanical garden
* Gymnocalycium species from Liberec botanical garden