Origin and Habitat: Widespread in the Central Peruvian Andes at high elevations from Oroya to Cuzco
Altitude: 3000-4700 metres above sea level.
Habitat: Oroya peruviana has adapted to survive in extremely rocky habitats that other plants can’t survive in because of the lack of soil (at least in large amounts) and how dry it is. The plants growing at higher altitutes are exposed to appreciable freezing in a tropical alpine climate where summer night-time temperatures can be -8° C.
Description: Oroya peruviana is an extremely variable slow-growing perennial cactus species that grows, as the Oreocereus do, in the high mountains of the Andes. It is (usually) solitary but may produce small clumps with age. The spines are very varied in form and colour and often appressed against the plant body in a manner reminiscent of a bird’s nest. Some specimens of this species bloom very profusely.
Stem: Depressed globose or hemispheric and deep-seated in the ground, that eventually becomes shortly columnar, much-ribbed, 10-14(-20) cm broad and 5-25(-30) cm tall. Epidermis bright green to blue-green.
Ribs: 12-35 (usually 21), low, obtuse, divided into low tubercles.
Areoles: Long, narrow 8 to 12 mm long, whitish, closely set, very woolly, on the extremity of a groove in the tip of tubercles.
Spines: Ranging in colour from pale yellow, to orangish, to coppery gold to brown with darker bases and reddish tips , barely distinguishable as centrals and radials.
Radial spines: 15 to 20, variable, more or less pectinated, slightly curved inward, unequal, the longer ones about 2 cm long (usually less than 1,5 cm long).
Central spines: Sometimes as many as 6, but often wanting, a little longer and stouter than the laterals and usually reddish-brown in colour.
Flowers: Small,1,5 to 2 cm long, bell to funnel-shaped, often very numerous, produced from young areoles, in a dense cluster or ring around the crown of the plant, pink-orange-red with a whitish to lemon yellow centre; outer perianth-segments acute, reddish, the inner pink, yellow at base, linear, obtuse or apiculate; style pink above; stigma-lobes pale yellow. Perianth tube very short and covered with small scales. The Areoles of hypanthium and Perianth tube are slightly woolly. Oroya flowers look very similar to Eriosyce flowers but shorter.
Blooming season: Spring to summer.
Fruit: More or less spherical or short club shaped, hollow berries, slightly fleshy, yellow or reddish brown., and covered with small scale. Flowers remnants persistent.
Seeds: Helmet-shaped, reddish-brown to black, approx. 2 mm long.