Autor: Philippi

“Woolly fig”, referring to the typical woolly fruit of most species of the genus.
A genus of usually large, solitary, globose plants, the apex more or less covered with wool, with fibrous roots, slightly turbiniform in E. rodentiophila. Ribs quite numerous (18-42 or more), usually tuberculate. Spines strongly aciculate, sturdy, strongly bent back upward.
Flowers diurnal, self-sterile, appearing depressed around the apex, cupulate, petals erect, pinkish to reddish, also yellowish, pollinated by insects (mostly solitary bees). Fruits often setose and densely woolly, floral remains persistent, consumed by rodents such as chinchillas (Chinchilla brevicaudata, C. chinchilla, the latter regrettably exinct, Lagidium sp.) and guanacos (Llama guanicoe). Seeds of variable size (1.8-3 mm), egg-shaped, black, slightly pitted, dispersed by rodents and guanacos.
The genus Eriosyce s.s. grows along the Pacific coast in the Atacama desert, up to the mountains of the Andes, in extremely arid areas, exclusively on mineral soils, with little or no surrounding vegetation, among masses of fallen rocks, in crevices or between rocks, practically from sea level (E. rodentiophila) up to approximately 2000 m in altitude (£. aurata).
• DISTRIBUTION (in the acceptance of Eriosyce s.s.)
Chile (Antofagasta, Atacama, Coquimbo).

Currently 3 recognised species, but it is possible that others are valid:
– Eriosyce aurata* (Pfeiff.) Backeb. 1936 (= E. ceratistes ? = Eriosyce sondillon ?)
– Eriosyce rodentiophila* F.Ritter 1980
– Eriosyce spinibarbis F.Ritter 1980

References: "TAXONOMY of the CACTACEAE" -  ISBN 978-84-617-3723-9 (Vol. 1)