Echinocereus rigidissimus rubrispinus

Echinocereus rigidissimus rubrispinis is a low growing solitary (very rarely few branched) cactus. This species is a great favorite in collections.  Each year’s growth is differentiated by differently coloured band of spines, hence the common name “Rainbow Cactus”. Flowers are bright pink with much lighter white throat, 6-7 cm long, 6-10 cm in diameter when expanded.

It grows on gravely hills, steep canyon sides, rocky benches in semidesert grasslands, oak woodlands, interior chaparral, mostly on igneous limestone substrates. The reported habitat preference for limestone is erroneous; this species is a calcifuge, preferring soils poor in lime and usually acid.