Body compressed spherical to cylindrical. Ribs 13-21 with a pointed ridge, often spiralled. Central spines 4 the lower one flattened and curved at the tip, radial spines 5-15. Flowers pink to white or yellow with densely distributed narrow scales on tube. Fruit with long tapering scales.

Mexico

A species known for its spectacular red or yellow spines.

There are 3 intergrading varieties: var. spiralis (Pfeiff.) N.P. Taylor which has spherical to cylindrical bodies often with spiralling ribs; var. greenwoodii (Glass) N.P. Taylor with spines of more or less equal thickness and var. latispinus which has 9-15 radial spines (5-7 in other varieties).

 

Ferocactus flavovirens (Scheidw.) Britton & Rose from S Mexico differs in having the lowermost spine more or less straight.

Source: Thompson, A, ; Forbes, S.; Spencer, R. (1997). Cactaceae. In: Spencer, R.. 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.