Scientific taxonomy article
Accepted name and publication history
The accepted name in the current Kew backbone is Gymnocalycium spegazzinii Britton & Rose. Britton and Rose published the name directly in Gymnocalycium in 1922 in The Cactaceae 3: 155. IPNI supplies nomenclatural authorship and place of publication, while current acceptance, synonymy, and native distribution follow POWO's taxonomic opinion.12
The accepted name is not a new combination. The historical names Echinocactus loricatus and Gymnocalycium loricatum are synonyms in the current backbone.
Taxon boundary and infraspecific treatment
In the Kaktüs Doktoru backbone, the species is a child of the genus Gymnocalycium. Kew recognizes two accepted subspecies: subsp. cardenasianum and subsp. spegazzinii. This package updates only the canonical species node and its linked botanical-dictionary record; it does not collapse accepted subspecies into species synonyms, rewrite the genus node, or alter the product.
Diagnostic characters
A depressed-globose stem, grey-green to bronze-brown epidermis, broad ribs, and strong spines curving close to the stem are assessed together in identification. These characters must be assessed together. A single commercial photograph is not an herbarium voucher, and colour, spine length, or stem form may shift with cultivation conditions.
Phylogenetic context
A broad plastid-DNA study recovered Gymnocalycium as monophyletic but found that several older morphology-only infrageneric groups were not natural: Microsemineum was polyphyletic and Macrosemineum paraphyletic. The study recommends reading seed morphology together with molecular evidence.3 This does not by itself change the accepted name of this species; it warns against inferring close relationship from one conspicuous surface character.
Native distribution and conservation
Kew records the native range as north-western Argentina and Bolivia.1 The species grows on arid mountain slopes and stony ground with a broad, low stem; a wild population and a commercial pot form are not equivalent evidence. The stored conservation category is LC.4 IUCN assesses the species as Least Concern. The category applies to wild populations and must not be confused with nursery stock or the separate ranges of accepted subspecies.
Synonymy and retrieval
Kew accepts 2 synonyms under this species node: Echinocactus loricatus and Gymnocalycium loricatum. These are not canonical routes; they document nomenclatural history and support retrieval of older literature.1
References
- Plants of the World Online. “Gymnocalycium spegazzinii Britton & Rose.” Royal Botanic Gardens, Kew. Accessed: 2026-08-04. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:115497-2 ↩
- International Plant Names Index. “Gymnocalycium spegazzinii Britton & Rose.” Accessed: 2026-08-04. https://www.ipni.org/n/115497-2 ↩
- Demaio, P. H. et al. “Molecular phylogeny of Gymnocalycium (Cactaceae).” American Journal of Botany 98(11): 1841–1854. https://doi.org/10.3732/ajb.1100054 ↩
- IUCN Red List of Threatened Species. “Gymnocalycium spegazzinii.” https://www.iucnredlist.org/species/152523/121538187 ↩
- World Flora Online. “Gymnocalycium spegazzinii Britton & Rose.” Accessed: 2026-08-04. https://www.worldfloraonline.org/taxon/wfo-4000016452 ↩
