Aylostera is a genus of small cacti in the family Cactaceae (order Caryophyllales), native to the Andean foothills of central Bolivia and north-western Argentina. The genus was erected by the Argentine botanist Carlo Luigi Spegazzini in 1923, later subsumed into a broadly defined Rebutia, and ultimately resurrected as a distinct genus following molecular phylogenetic studies beginning in 2007 that demonstrated Rebutia in its broad sense was not monophyletic. A 2016 study using both molecular and morphological evidence confirmed that Aylostera is monophyletic and distantly related to the clade containing the type species of Rebutia, and the genus is accepted by Plants of the World Online as of December 2024. A 2023 classification of the tribe Cereeae placed Aylostera as the sole genus in the subtribe Aylosterinae.
Plants in this genus are characterised by globular to shortly columnar stems that may or may not bear ribs — a feature that can vary even between individuals of the same species. Their flowers are produced in a range of colours, typically vibrant reds, oranges, and yellows. The most reliable morphological character separating Aylostera from the closely allied Rebutia is that the pericarpels and receptacles — collectively forming what is often called the flower tube — are covered in hairs, whereas those of Rebutia are glabrous.
The genus encompasses species distributed across Bolivia and north-western Argentina, growing on the cordilleras east of the Andes between approximately 17° S and 26° S latitude, in montane dry forests, shrublands, and dry puna grasslands. Species counts vary considerably by authority: the 2016 monograph accepted nine species (including a broadly circumscribed Aylostera deminuta), while Plants of the World Online recognised 26 species as of December 2024. Well-known members include Aylostera deminuta, Aylostera heliosa, and Aylostera fiebrigii, all valued by cactus enthusiasts for their compact habit and prolific flowering.
Etymology
The genus name Aylostera was coined by the Argentine botanist Carlo Luigi Spegazzini in 1923. Wikipedia does not record the derivation of the name, and no classical Greek or Latin etymology has been identified from available sources.
Distribution
Aylostera species are native to Bolivia and north-western Argentina. They are found on the cordilleras east of the Andes, between approximately 17° S and 26° S latitude, growing in montane dry forests, shrublands, and dry puna grasslands.
Ecology
Aylostera inhabits high-altitude Andean habitats along the eastern cordilleras, including dry montane forests, shrublands, and puna grasslands — environments characterised by strong seasonal drought, intense solar radiation, and cool to cold temperatures. These conditions have driven the genus's characteristic compact, globular growth form and have contributed to the plants' popularity in cultivation, where their natural tolerance of drought and cool winters is readily exploited.
Cultivation
Aylostera species are widely cultivated by cactus enthusiasts worldwide, prized for their compact size, ease of culture, and abundant, brightly coloured flowers produced even on young plants. They thrive in free-draining mineral or sandy compost, bright light, and a dry, cool resting period in winter — conditions that mimic their native high-altitude Andean habitats. Most species tolerate light frost when kept dry. Propagation is typically by offsets, which are freely produced, or from seed.
Taxonomy Notes
The taxonomic history of Aylostera is intertwined with that of Rebutia. The genus was established by Spegazzini in 1923 but was subsequently sunk into a broadly circumscribed Rebutia for much of the 20th century. Molecular phylogenetic work from 2007 onwards revealed that Rebutia in this broad sense was polyphyletic, prompting the resurrection of Aylostera. A comprehensive 2016 study combining molecular and morphological data confirmed that Aylostera is monophyletic and distantly related to the Rebutia type-species clade. Some taxonomic checklists (including one GBIF backbone) still treat Aylostera Speg. as a synonym of Rebutia K.Schum., while Plants of the World Online accepts it as a distinct genus. A 2023 classification placed it as the sole genus of the subtribe Aylosterinae within the tribe Cereeae.
