Gymnocalycium


Gymnocalycium, commonly called chin cactus, is a genus of about 70 South American species of cactus. The genus name Gymnocalycium 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 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 2023:
ImageScientific nameDistribution
Gymnocalycium affine ŘepkaArgentina
Gymnocalycium alboareolatum RauschArgentina
Gymnocalycium alenae KulhánekArgentina
Gymnocalycium amerhauseri H.TillArgentina
Gymnocalycium andreae Backeb. & F.M.KnuthArgentina
Gymnocalycium angelae Mereg.Argentina
Gymnocalycium anisitsii Britton & RoseBolivia to Paraguay
Gymnocalycium × applanatum Řepka & Frélich Argentina
Gymnocalycium baldianum Speg.Argentina.
Gymnocalycium basiatrum F.Berger, Amerh. & SedlmeierArgentina
Gymnocalycium bayrianum Till ex H.TillArgentina
Gymnocalycium berchtii NeuhuberArgentina
Gymnocalycium bodenbenderianum A.BergerArgentina
Gymnocalycium bruchii HosseusArgentina
Gymnocalycium cabreraense Schädlich, Bercht & MelojerParaguay
Gymnocalycium calochlorum Y.ItôArgentina
Gymnocalycium campestre ŘepkaArgentina
Gymnocalycium capillense HosseusArgentina
Gymnocalycium castellanosii Backeb.Argentina
Gymnocalycium chacoense Amerh.Bolivia
Gymnocalycium chiquitanum CárdenasBolivia.
Gymnocalycium denudatum Pfeiff. ex MittlerS. Brazil to Argentina
Gymnocalycium erinaceum J.G.Lamb.Argentina
Gymnocalycium esperanzae Řepka & KulhánekArgentina
Gymnocalycium eurypleurum F.RitterParaguay
Gymnocalycium gibbosum Pfeiff. ex MittlerArgentina.
Gymnocalycium glaucum F.RitterArgentina.
Gymnocalycium horstii BuiningBrazil.
Gymnocalycium hossei A.BergerArgentina
Gymnocalycium kieslingii O.FerrariArgentina.
Gymnocalycium kroenleinii R.Kiesling, Rausch & O.FerrariArgentina.
Gymnocalycium kuehhasii Neuhuber & R.SperlingArgentina.
Gymnocalycium kulhanekii PapschArgentina
Gymnocalycium marekiorum MiltBolivia
Gymnocalycium marsoneri Frič ex Y.ItôArgentina
Gymnocalycium mendozaense C.A.L.Bercht & SchädlichParaguay.
Gymnocalycium mesopotamicum R.KieslingArgentina
Gymnocalycium mihanovichii Britton & RoseParaguay to Argentina
Gymnocalycium × momo V.Gapon & Schelkun. Argentina
Gymnocalycium monvillei Pfeiff. ex Britton & RoseArgentina
Gymnocalycium mostii Britton & RoseArgentina
Gymnocalycium neuhuberi H.Till & W.TillArgentina
Gymnocalycium nigriareolatum Backeb.Argentina
Gymnocalycium ochoterenae Backeb.Argentina
Gymnocalycium oenanthemum Backeb.Argentina
Gymnocalycium paediophylum SchützParaguay.
Gymnocalycium paraguayense HosseusParaguay.
Gymnocalycium pflanzii Werderm.Bolivia to Paraguay.
Gymnocalycium pinalii Mereg. & KulhánekArgentina
Gymnocalycium ponomarevae V.Gapon & NeuhuberArgentina
Gymnocalycium quehlianum Vaupel ex HosseusArgentina.
Gymnocalycium ragonesei A.Cast.Argentina
Gymnocalycium reductum Pfeiff. ex MittlerArgentina
Gymnocalycium rhodantherum H.TillArgentina
Gymnocalycium ritterianum RauschArgentina.
Gymnocalycium robustum R.Kiesling, O.Ferrari & MetzingArgentina
Gymnocalycium saglionis Britton & RoseArgentina
Gymnocalycium sanluisense NeuhuberArgentina.
Gymnocalycium schickendantzii Britton & RoseArgentina.
Gymnocalycium schroederianum OstenArgentina to Uruguay.
Gymnocalycium spegazzinii Britton & RoseArgentina.
Gymnocalycium stenopleurum F.RitterSE. Bolivia to N. Paraguay.
Gymnocalycium striglianum Jeggle ex H.TillArgentina
Gymnocalycium taningaense PiltzArgentina
Gymnocalycium uebelmannianum RauschArgentina
Gymnocalycium uruguayense Britton & RoseS. Brazil to Uruguay
Gymnocalycium victorii NeuhuberArgentina
Gymnocalycium volskyi V.Gapon, Ponomareva, Protopopov, Schelkun. & ZaitsevaUruguay

Distribution

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