Echinocereus rigidissimus, commonly known as the Arizona Rainbow Cactus or Rainbow Hedgehog Cactus is a solitary, growing cactus, that rarely branches or offsets with age.
Echinocereus rigidissimus grows to a height of up to 30 cm, and a width of 11 cm when mature, with pectinate radial spines curved slightly towards the stem, the new spines are initially reddish to magenta and fades to a yellow or light pink colour when they mature.
Echinocereus rigidissimus, flowers
(Wikipedia)