''Aylostera'', is a genus of

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, ...

, native to central Bolivia and north western Argentina. ''Aylostera'' was formerly sunk into a broadly

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

genus ''

Rebutia ''Rebutia'' is a genus of flowering plants in the family Cactaceae, native to Bolivia and Argentina. The limits of the genus have varied widely, depending on whether genera such as ''Aylostera'' and ''Weingartia'' are included or treated separate ...

'', but

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies from 2007 onwards showed that when defined in this way, ''Rebutia'' was not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

, leading to the resurrection of ''Aylostera''. 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 ...

placed it as the only genus in the subtribe Aylosterinae. It was formerly placed in the subtribe

Rebutiinae The Rebutiinae are a subtribe of cactus, cacti belonging to the subfamily Cactoideae, tribe Cereeae. A 2010 classification accepted seven or eight genera, but when Circumscription (taxonomy), circumscribed in this way, the subtribe was not Monoph ...

Description

''Aylostera'' species are small cacti with globular stems. The stems may or may not have ribs; this feature can vary even within a species. Their flowers are of various colours. A key feature that distinguishes ''Aylostera'' from ''Rebutia'' is that the pericarpels and receptacles (which together form a structure that is often referred to as the 'flower tube') are hairy, rather than

glabrous Glabrousness () is the technical term for a lack of hair, down, setae, trichomes, or other such covering. A glabrous surface may be a natural characteristic of all or part of a plant or animal, or be due to loss because of a physical condition, ...

Taxonomy

The genus ''Aylostera'' was erected by

Carlo Luigi Spegazzini Carlo Luigi Spegazzini, in Spanish Carlos Luis Spegazzini (20 April 1858 – 1 July 1926), was an Italian-born Argentinian botanist and mycologist. On the 1881/1882 expedition led by Giacomo Bove to explore Patagonia and Tierra del Fuego, ...

in 1923. A historical summary of the treatment of ''Aylostera'' and related genera published in 2011 showed how in succession it was recognized, sunk into ''Rebutia'', and then resurrected to include a large part of ''Rebutia''. A phylogenetic study in 2016 using both molecular and morphological characters confirmed that ''Aylostera'' was monophyletic and distantly related to the clade that contains the type species of ''Rebutia'', thus justifying recognizing it as a separate genus. The separate status of ''Aylostera'' is accepted by

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 ...

, . In a 2023 classification of the tribe

, it was placed as the only genus in the subtribe Uebelmanniinae, having formerly been placed in the subtribe

Species

The number of species accepted in ''Aylostera'' varies considerably. The 2016 study of the genus accepted only nine species, including a very broadly circumscribed ''

Aylostera deminuta ''Aylostera'', is a genus of cactus, native to central Bolivia and north western Argentina. ''Aylostera'' was formerly sunk into a broadly Circumscription (taxonomy), circumscribed genus ''Rebutia'', but Molecular phylogenetics, molecular phyloge ...

''. , Plants of the World Online accepted 26 species:

Distribution and habitat

''Aylostera'' species are native to

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 north-western

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 ...

. They are found on the

cordillera A cordillera is a chain or network of mountain ranges, such as those in the west coast of the Americas. The term is borrowed from Spanish, where the word comes from , a diminutive of ('rope'). The term is most commonly used in physical geogra ...

s to the east of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

, from 17° south to 26° south, in montane dry forests, shrublands and dry puna grasslands.

References

Cereeae Endemic flora of Bolivia Flora of Northwest Argentina Taxa described in 1923 Cereeae genera {{Cactus-stub