''Gymnocalycium'', commonly called chin cactus, is a genus of about 70

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

cactus A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...

. The genus name ''Gymnocalycium'' (from

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

, "naked calyx") refers to the flower buds bearing no hair or spines. In a 2023 classification of the tribe

Cereeae Cereeae is a tribe of cacti belonging to the subfamily Cactoideae containing about 50 genera, divided in 2023 among six subtribes. Description Cereeae are tree-like or shrubby, sometimes climbing plants. Their mostly elongated to spherical, rib ...

, 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

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are generally brightly colored.

Species

Species of the genus ''Gymnocalycium'' according to

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

Distribution

Their main area of distribution is

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

, part of

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

and part of

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

Gallery

File:Gymnocalycium Liberec 1.jpg, ''Gymnocalycium'' species from

Liberec Liberec (; ) is a city in the Czech Republic. It has about 108,000 inhabitants, making it the fifth largest city in the country. It lies on the Lusatian Neisse River, in a basin surrounded by mountains. The city centre is well preserved and is pr ...

botanical garden File:Gymnocalycium Liberec 2.jpg, ''Gymnocalycium'' species from

botanical garden File:Gymnocalycium Liberec 3.jpg, ''Gymnocalycium'' species from

botanical garden

References

External links

SucculentCity: ''Gymnocalycium'' Page
* * {{Authority control Cereeae genera Cacti of South America Flora of Argentina Flora of Bolivia Flora of Brazil Flora of Paraguay Flora of Uruguay Garden plants of South America