Subspecies, varieties, forms and cultivars of plants belonging to the Ferocactus pottsii complex

(This Taxon belong to a group of six closely allied species. The group is: Ferocactus alamosanus, Ferocactus schwarzii, Ferocactus reppenhagenii, Ferocactus glaucescens, & Ferocactus echidne)

• Ferocactus alamosanus Britton & Rose: has usually about 20 acute ribs, heavy spination, and only grows to 25 cm high.
• Ferocactus glaucescens (DC.) Britton & Rose: glaucous (blue grey-green) with nice light golden spines, as the plant ages can form a very large mound.
• Ferocactus glaucescens f. cristata: Crested form.
• Ferocactus glaucescens f. nudus cristatus monstuosus clone A: crested form of Ferocactus glaucescens cv. Split Rock with irregular fan-shaped stem, that looks like an old weathered rock.
• Ferocactus glaucescens f. nudus cristatus monstuosus clone B: crested form with irregular fan-shaped stem and areoles often merging to form horizontal bands.
• Ferocactus glaucescens f. nudus cristatus: Crested form.
• Ferocactus glaucescens f. nudus: spines are absent or very few (1 to 3 not distinguishable from radials to centrals) irregularly scattered on the areoles of young individuals.
• Ferocactus glaucescens f. variegatum hort.: has sectors, patches or stripes with distinct shades of yellow.
• Ferocactus glaucescens cv. Split Rock hort.: is monstrous barrel cactus that looks like an old weathered rock. The epidermis starts soon to split open assuming the appearance of a rock surface.
• Ferocactus hybrid alamosanus x schwarzii hort.
• Ferocactus hybrid alamosanus x schwarzii f. variegatus hort.
• Ferocactus reppenhagenii G.Unger: has 12-18 rounder ribs and connecting areoles and will grow up to about 70-100 cm.
• Ferocactus reppenhagenii f. cristatus hort.: crested form.
• Ferocactus schwarzii G.E.Linds.: Younger plants have usually 4 to 5 (or more) gold coloured spines. As they age the number of spines decreases and old plant are nearly spineless or have only 1 or 2 spines.