Opuntia invicta

Native to Central Baja California, Mexico, Grusonia invicta (Corynopuntia invicta) is a mat forming cactus that grows approximately 20-50 cm high and up to 2m across (or more) with stout stems and very broad formidable spines. Stems: Jointed, deep green ascending or spreading. Segments obovoid to club-shaped, up to 12 cm long. Strongly tuberculate Tubercles: Large, flattened laterally, 3-4 cm long Areoles: Large up to 1,5 cm in diameter with white wool Glochids: Few white up to 4 mm long Leaves: Linear, slightly curved, reddish and ephemeral, 8-14 mm long Spines: Thick, sharp-pointed, straight and strongly flattened, that look like little daggers, 1-5 cm long, and are at first reddish or purple with bright carmine-red base, turning greyish-white and finally black. Radial spines: 6-10 Central spines: 10-12 much stouter than the radials Flowers: Yellow up to 5 cm in diameter, with a magnificent form. Tepals ovate-acuminate. Ovary almost hidden by numerous reddish acicular spines Blooming season: April to May Seeds: Yellowish, 2 mm broad Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz