F. chrysacanthus with red spines is one of the best and colourfull Ferocacti. This is somewhat of a slow growing species. This plant is very densely spined and because of that, will tolerate full sun. 

A young seedling

Description: Solitary barrel cactus. The plant is very densely spined (one of the spiniest of the Ferocacti) and because of that, will tolerate full sun. This beautiful and rare form has bright red  thick, twisted and more or less hooked spines.

Cultivation: It is often  recommended to graft young seedlings on Eriocereus jusbertii or Pereschiops. But plant can grow on their own roots for ages if watered carefully.

Conservation status: Listed in CITES appendix 2.

Ferocactus chrysacanthus f. rubrispinus (L.M. Ford ex Orcutt) G. Unger
In: Die grossen Kugelkakteen Nordamerikas 210, 1992.

Origin: Mexico (Baja California: Only occurs naturally on the island of Cedros, off the west coast of northern Baja California and possibly on a neighboring island, West San Benitos, with some reports of it on the adjacent peninsula.)

Habitat: With balanced and relatively high average temperature, low rainfall but relatively high humidity and specific soil composition (these conditions are difficult to imitate in cultivation, and make this species relatively problematic to grow.

Photo of conspecific taxa, varieties, forms and cultivars of Ferocactus chrysacanthus:

• F. chrysacanthus
• F. chrysacanthus f. rubrispinus