Cactaceae
Succulent perennial herbs or shrubs; stems columnar, cylindric or flattened, often jointed and spiny. Lvs usually 0 or very reduced and caducous. Branches often furnished with areoles (± circular, cushion- like patches). Fls solitary, ⚥, usually actinomorphic. Calyx often petaloid and grading into petals. Petals numerous, in several series, the innermost largest, sometimes coherent at base. Stamens numerous, free or adnate to base of petals. Ovary inferior, 1-locular, with 3 or more parietal placentas. Ovules numerous; style 1; stigmas 2-many. Fr. a berry, often spiny or bristly. Seeds usually numerous, immersed in pulp.
170-220 genera, up to c. 2000 spp., drier regions of America, mainly tropical and subtropical, with 1 genus in Africa, Sri Lanka and the Indian Ocean Is.
There are a large number of cacti cultivated in N.Z., often in glasshouses, but in warm coastal areas some can be grown outside, particularly on well-drained or dry slopes.
