Eriosyce is a genus of cacti in the family Cactaceae (order Caryophyllales), endemic to Chile. The genus comprises roughly ten accepted species, all adapted to the arid and semi-arid landscapes of the Atacama Desert region and adjacent Andean foothills.
Plants are typically solitary, globose to short-cylindrical in form, rarely offsetting, and can reach up to 1 metre in height with a diameter of up to 50 centimetres. The stem surface is divided into 7 to 30 prominent ribs, along which spine-bearing areoles are arranged at regular intervals; the ribs are noticeably constricted between areoles, giving the stem a tuberculate appearance. Spines are stout and often numerous.
Flowers are borne near the apex of the plant, are funnel-shaped, and range in colour from yellow to deep red. The fruit is a hollow, often woolly berry that characteristically splits open at the base when ripe, releasing seeds that are typically loose within the cavity. Seeds are small, ranging from 0.7 to 3 mm in length.
Notable species include Eriosyce aurata, a widely recognised species known for its dense golden spines, and Eriosyce napina, a small geophytic cactus with a turnip-like taproot that grows almost entirely underground in Chile's Atacama Desert.
Etymology
The genus name Eriosyce derives from the Greek erion (wool) and sykon (fig), referring to the woolly, fig-like appearance of the fruit. This reflects the characteristically wool-covered hollow berries that are diagnostic for the genus.
Distribution
Eriosyce is endemic to Chile, occurring across a range of arid to semi-arid habitats from the Atacama Desert coastal zone to the Andean foothills. The genus is not recorded from Argentina or other neighbouring countries.
Taxonomy Notes
Eriosyce has historically been treated as a broadly circumscribed genus absorbing several formerly separate genera, including Neoporteria, Pyrrhocactus, Islaya, and Horridocactus, following revisions that recognised their close phylogenetic relationships. Some authorities still use these segregate names. GBIF currently recognises approximately 9 accepted species. Plants of the World Online is used as the authority for accepted species in this genus.
