The genus includes 4 well-defined species, all natives of the Andes and of Bolivia and Peru. They make handsome plants, covered in longish hairs and bearing numerous strong, yellow spines, 2 inches in length. Theare dark red.
Oreocereus celsianus. A lovely species of rather slow growth, often branching from the base. Thehave 9 to 17 ribs; the areoles are woolly and whitish, bearing a cluster of slender yellowish-brown radial spines, and 1 to 4 centrals. The plant requires a consisting of 1 part silver sand, 1 part loam, and 1 part soil, and should be freely watered during the warm weather.
Oreocereus Trollii. A low-growing species, thelight green, with about 9 ribs. The large, oval areoles are furnished with creamy white or light grey wool, about 7 radial spines, and 1 to 3 central spines which are longer and stouter. Hairs, at first silky and creamy white, afterwards woolly and dirty white, entirely cover the stem. Popularly known as “the old man of the Andes , the plant is easily cultivated. And requires the same treatment as O. celsianus. S
It will grow better when grafted on Cereiis stock, but it has been noticed that it is not free flowering.