Body mostly solitary with huge barrel-like to cylindrical strongly ribbed stems. Areoles large, elongated and more or less continuous in mature plants and forming a woolly crown on the body; nectar secreting glands absent. Spines strong. Flowers arising at the body apex, funnel to bell-shaped mostly pink or yellow; summer. Pericarpel with narrow scales bearing wool in their axils. Fruit pale yellow, fleshy to almost dry.
The 3 commonly grown species are keyed out in the key. E. horizonthalonius Lem. may, like E. texensis Hopffer, be better placed in Homalocephala Britton & Rose, while E. platyacanthus Link & Otto is often grown under the synonym E. ingens Zucc.
Ferocactus is rather similar but has the nectar-secreting glands on the areoles.
This genus at one time contained nearly all the cacti with ribbed stems, other than those in Cereus and Melocactus; it is now best known through the huge E. grusonii which forms large spiky balls characteristic of globose cacti.
Large barrel-shaped to cylindrical, srongly ribbed, thickly spined bodies
3 species as considered here from N Mexico and SW USA.
Source: (1997). Cactaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.