Commemorating Mexican President Olvaro Obregon.
Body compressed spherical, mostly to about 20 cm wide, grey-green with a thick taproot. Tubercles arising in a rosette, deeply cut like an artichoke and flattened, 3-angled and with a basal ridge. Areole small, at tip of tubercle and with up to 5 variously curved weak and often rapidly shed spines. Flowers to about 4 cm long, borne at the woolly body apex on young tubercles, whitish or pale pink; filaments pink. Pericarpel and tube well developed but often buried in wool; naked. Fruit club-shaped, fleshy becoming dry, with white flesh.
Possibly related to Lophophora. The sole species is O. denegrii Fric.
Seed, offsets or grafting.
Tubercles arising in a basal rosette, large, 3-angled and flattened, ridged below with areoles at the tips; spines soon shed.
1 species from NE Mexico (Tamaulipas).
Source: (1997). Cactaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.
