Scientific taxonomy article
Accepted name, authorship, and first publication
The 2026 Kew backbone accepts Aylostera muscula; the standardized author citation is (F.Ritter & P.Thiele) Backeb. Backeberg published the accepted combination in 1963 in Descriptiones Cactacearum Novarum 3: 5; the basionym is Ritter and Thiele’s Rebutia muscula, published that year in Taxon 12: 29. IPNI records nomenclatural authorship and place of publication, while current acceptance, native distribution, and the species synonym surface follow POWO.12
A basionym or former combination does not mean that the current species name is “wrong.” Nomenclature tracks how the same type has been named in different genera or ranks. Rebutia muscula F.Ritter & P.Thiele is therefore retained as a historical bridge, while the Kaktüs Doktoru canonical species route remains under Aylostera muscula.
The Aylostera–Rebutia boundary and source opinions
A 2016 cpDNA and AFLP study recovered Aylostera as monophyletic, supported its separation from the clade containing the type species of Rebutia, and identified three principal clades.3 The same work proposed a narrower classification recognizing nine species from molecular and morphological evidence. The maintained Kew backbone accepts Aylostera muscula as a distinct species.14
The World Flora Online/Caryophyllales backbone retains a broader Aylostera deminuta treatment and links some names in this batch to that synonym surface.5 This difference is not hidden behind a claim that one source is simply “wrong.” Kaktüs Doktoru follows the current Kew acceptance for its canonical node and records WFO as an alternative taxonomic application. Readers can therefore understand why older or broader sources may retrieve the same material under Rebutia or a broad A. deminuta concept.
Species boundary and synonymy
Kew accepts 2 synonyms at the species node: the homotypic Rebutia muscula and the heterotypic Rebutia muscula var. luteoalbida. These rows are not canonical routes; they preserve retrieval of the basionym, former generic combinations, and historical species applications. Two active products share the botanical node. The taxonomy-only package changes neither; the legacy prod-rebutia-muscula record retains its one product translation and two canonical slugs exactly as found. Synonym count is not a count of wild populations or a measure of conservation security. Heterotypic synonyms in particular show that historically described taxa based on different types have been united by the current backbone; they do not imply that every living specimen is morphologically identical.
The accepted species node owns only names supported for that species. Related species, commercial cultivars, colour selections, and product labels are not added unless the maintained botanical backbone treats them as synonyms. This prevents search visibility from flattening taxonomy.
Diagnostic characters
Small offsetting bodies, numerous fine white soft-looking spines that largely obscure the green epidermis, and bright orange flowers are evaluated together. A “white-haired” appearance alone does not automatically turn A. albipilosa or broad A. fiebrigii usages into Muscula synonyms. Members of Aylostera are recognized through small globose to short-cylindrical bodies, tuberculate surfaces, areole and spine arrangements, and flowers large relative to the stem. The 2016 key uses combinations of characters rather than one photographic feature.3
Identification should evaluate body shape, tubercle pattern, areole spacing, number and direction of radial and central spines, floral tube, flower colour, fruit, seed, and reliable provenance. Nursery conditions can alter spine length, epidermal colour, offsetting, and flowering time. A product photograph is therefore neither a record of a wild population nor a nomenclatural type.
Native range, habitat, and conservation
Kew records the native range as Tarija, Bolivia and describes the species as a succulent subshrub of desert or dry-shrubland biomes.1 Kew records the species from Tarija, Bolivia, as a succulent subshrub of desert or dry-shrubland biomes. Provenance is narrower evidence than a generic white-spined commercial Rebutia label. The geographic statement describes wild distribution rather than the place of commercial production; nursery availability must not be confused with habitat security.
Because Kew exposes no verified global IUCN assessment on the accepted Muscula page or its synonym data, the unsupported live LC value is cleared to null. A modelled prediction or a related species assessment is not substituted for an official assessment. When no official assessment is available, an empty field is more accurate than an inferred confidence label.
Kaktüs Doktoru release and ownership boundary
This source updates only the species taxonomy node and its linked botanical-dictionary record. Two active products share the botanical node. The taxonomy-only package changes neither; the legacy prod-rebutia-muscula record retains its one product translation and two canonical slugs exactly as found. Product descriptions, stock, price, SKU, media, categories, variants, product translations, canonical slugs, and product–botanical links are not owned by the payload. They remain protected live-state evidence for disposable and production verification.
References
- Plants of the World Online. “Aylostera muscula (F.Ritter & P.Thiele) Backeb..” Royal Botanic Gardens, Kew. Accessed: 2026-08-04. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:27588-2 ↩
- International Plant Names Index. “Aylostera muscula (F.Ritter & P.Thiele) Backeb..” Accessed: 2026-08-04. https://www.ipni.org/n/27588-2 ↩
- Ritz, C. M. et al. “Molecular phylogenetic relationships of the Andean genus Aylostera Speg. (Cactaceae, Trichocereeae), a new classification and a morphological identification key.” Plant Systematics and Evolution 302: 763–780. https://doi.org/10.1007/s00606-016-1296-4 ↩
- Plants of the World Online. “Aylostera Speg.” Royal Botanic Gardens, Kew. Accessed: 2026-08-04. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:295167-2 ↩
- World Flora Online. “Aylostera deminuta (F.A.C.Weber) Backeb.” Accessed: 2026-08-04. https://www.worldfloraonline.org/taxon/wfo-0000557641 ↩
