Description of a new species
Pauca-Tanco and Hoxey described Corryocactus volcanicus in “Phytotaxa” on 12 December 2025. POWO accepts the name as a separate species. Type material Hoxey and Pauca 237 was collected above Andagua on 1 March 2024, at 3740 m above sea level. The holotype is in the HSP herbarium. The species name refers to the volcanic landscape of the Andagua Valley. [Pauca-Tanco and Hoxey 2025, typ, etymologia] [2-WWW]
Stem and areoles
In the species description, the plant reaches 3 m in height and branches from the base. Stems are upright, light green and 10–12 cm in diameter. They have 7–10 ribs, 22–28 mm high. Round areoles are spaced 21–30 mm apart. Older ones have greyish felt, while new ones have dark felt with a small brown tuft near the rib. Small triangular scales are also visible in young areoles. [Pauca-Tanco and Hoxey 2025, opis]
Stem spines are usually straight, sometimes slightly curved, with a smooth surface. They are yellow when young and later turn grey. The division into central and radial spines is unclear. The description usually gives 14–17 spines per areole, with broader variation in the basal part of an old stem. A count from one young areole therefore does not describe the whole plant. [Pauca-Tanco and Hoxey 2025, opis]
A pale flower and short style
Flowers usually develop near the tip, open during the day and have a funnel-shaped, radially symmetrical perianth. The open flower is 50–53 mm in diameter. Inner tepals are very pale yellow, almost white, with a faint pink tip. Scales, hairs and spines cover the exterior surrounding the ovary and floral tube. [Pauca-Tanco and Hoxey 2025, flower description]
The style is short and thick. A nectar chamber lies at its base. Numerous stamens surround the pistil, and the stigma divides into many papillose lobes. The diagnosis distinguishes the pale colour of the perianth and staminal organs, smaller flower dimensions and absence of the constriction between the ovary-surrounding part and tube that occurs in C. brevistylus. [Pauca-Tanco and Hoxey 2025, opis, diagnoza]
Flexible fruit spines and seeds
The fruit is spherical, greenish yellow, with translucent pulp and an acid taste. Areoles on its surface produce numerous thin, yellowish, flexible spines. This softness distinguishes it from the fruit of C. brevistylus. Seeds are brownish black, broadly oval and asymmetrical, with a mucilaginous covering and a dull, rough surface. [Pauca-Tanco and Hoxey 2025, fruit and seed description]
In the diagnosis, the main seed-length range for C. volcanicus is 1.76–1.90 mm, compared with 2.08–2.25 mm for C. brevistylus. The full description of the new species also includes an occasional measurement of 1.95 mm. The difference is part of a set of features, together with flower colour and dimensions and fruit-spine structure. The size of the measurement series was not given in the open taxonomic account. [Pauca-Tanco and Hoxey 2025, diagnosis, seed description]
Volcanic valley and development season
The known range is restricted to the Río Andagua basin in Valle de los Volcanes, at elevations of 2700–3800 m above sea level. Plants grow on slopes and flatter ground, in rocky or sandy substrates, often among volcanic scoria. In some places, they form dense stands of tall stems. The authors recorded flowering from August to November, fruit development from December and ripe fruits in late January. This is the Southern Hemisphere season. [Pauca-Tanco and Hoxey 2025, range and habitat]
High mountain ranges surround the valley, and its lowest parts are extremely dry. The authors consider this geography a possible cause of population isolation and species differentiation. This is a biogeographical hypothesis. Recognition in the protologue rests on morphological comparison, without genomic dating of this particular lineage. [Pauca-Tanco and Hoxey 2025, dyskusja]
Threats within a restricted area
Threats associated with small-scale mining and human-caused fires were observed in the valley. The protologue's authors propose the category Endangered, EN, under IUCN criteria relating to restricted range and habitat deterioration. This status was given in the new species description as the result of their threat assessment. [Pauca-Tanco and Hoxey 2025, stan ochrony]