A new Gymnocalycium species (Cactaceae) from Valle Fértil, San Juan, Argentina
Year: 2026
Type: article
Abstract: Background and aims: Although the flora of the Argentine Province of San Juan is, on the whole, well researched and documented, the distribution of plant species in more inaccessible areas is not yet fully known. This is particularly true of small herbaceous species, even those belonging to the Cactaceae family, which, due to their horticultural interest, are generally already among the better-studied species. A few years ago, an unknown population of the genus Gymnocalycium was discovered. M&M: The plants were studied in situ during several field trips, and specimens were collected for the herbarium and for further ex situ studies. For comparison purposes, specimens of other species were examined both in their natural habitat and in cultivation, and the relevant literature was consulted. Results and Discussion: The new finding belongs to Gymnocalycium subg. Gymnocalycium, for which no representative was previously known in the flora of San Juan. Due to morphological characteristics differs from other species of this subgenus found in neighbouring but clearly isolated mountain ranges in the provinces of Córdoba and La Rioja. The plants are therefore described here as a species new to science, Gymnocalycium justomarquezii sp. nov. An updated key to the identification of the genus Gymnocalycium in the Province of San Juan is presented. Two further cactus species, Denmoza rhodacantha and Cereus hankeanus, are here for the Sierra del Valle Fértil for the first time. Conclusions: The new species Gymnocalycium justomarquezii is endemic to the Sierra del Valle Fértil, emphasising the importance of this biodiversity hotspot. More field research isneeded to determine the distribution area and conservation status of this species.
Authors: Roberto Kiesling, Detlev Metzing
Language: English
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7166318538