Copiapoa taltalensis (Werd.) Looser, Revista Chilena Hist.Nat. 33:614 (1929)
Basionym: Echinocactus taltalensis Werd. Notizbl. Bot.Gart. Berlin Dahlem 97 (1929)

Copiapoa taltalensis has been considered closely related to C. humilis by various authors such as Hutchison and Ritter, and subsequently combined as a variety under C. humilis by Hoffmann. It could well have been that the name was mistakenly applied to the Copiapoa humilis from Guanillos. Having read the original description of C. taltalensis and visited the type location I can confirm that it is not closely related to C. humilis. The singular bodies, approximately 50mm across, are strongly ribbed without tubercles with a very green epidermis. The plants do not exhibit a distinct juvenile phase and the spination, both centrals and radials, is much stronger than any C. humilis taxon. It does however have a large tuberous root. Anderson included this taxon within the Copiapoa rupestris/rubriflora/desertorum complex, and it appears to be the most southerly growing form. This causes some re-arrangement of the nomenclature as Copiapoa taltalensis is the oldest name for this group so must be used in preference to the better known C. rupestris.

Figure 27 Copiapoa taltalensis PH453.01 (Esmeralda 450m)
This taxon has mistakenly been placed under C.humilis