Discocactus heptacanthus

Scientific Name: Discocactus heptacanthus (Barb.Rodr.) Britton & Rose
Synonym: Discocactus boliviensis, Discocactus cangaensis, Discocactus catingicola ssp. rapirhizus , Discocactus catingicola var. griseus , Discocactus crassispinus ssp. araguaiensis , Discocactus crassispinus, Discocactus diersianus ssp. goianus , Discocactus estevesii, Discocactus flavispinus, Discocactus goianus, Discocactus griseus, Discocactus hartmannii var. patulifolius , Discocactus hartmannii ssp. setosiflorus , Discocactus hartmannii, Discocactus hartmannii ssp. giganteus , Discocactus heptacanthus ssp. melanochlorus , Discocactus lindaianus, Discocactus magnimammus ssp. bonitoensis , Discocactus mamillosus, Discocactus melanochlorus, Discocactus nigrisaetosus, Discocactus pachythele, Discocactus paranaensis, Discocactus patulifolius, Discocactus piauiensis, Discocactus promentigibbus, Discocactus rapirhizus, Discocactus semicampaniflorus, Discocactus silicicola, Discocactus silvaticus, Discocactus spinosior, Discocactus squamibaccatus, Discocactus subterraneo-proliferans, Echinocactus hartmannii, Malacocarpus heptacanthus
Family: Cactaceae

Origin: Bolivia, Brazil, Paraguay

Growth Habits: Solitary, light green stems, 3.2 to 10 inches in diameter (8-25 cm), 2.8 to 6 inches tall (7-15 cm); 10-14 ribs; 5 to 11 spines.

This species is very variable and many names that are considered here included in it are still used in the trade:
D. boliviensis is 10 to 11 inches in diameter (25-28 cm), has 12 to 13 ribs, 5 whitish spines, 2 inches long (5 cm), pale pink flowers, in summer.
D. cangaensis is 5.2 inches in diameter (13 cm), has 10 to 14 tuberculate ribs, occasionally a central spine, 5 to 9 radials, white nocturnal flowers, up to 3 inches long (7.5 cm).
D. crassispinus has 15 ribs; 4 to 6 spines

Blooming Habits:
White nocturnal flowers in summer, 2 to 3 inches long (5-7.5 cm)