Greek pachys—thick.
Body mostly extremely large wide, erect and columnar. Areoles mostly felted, close-set or connected by a groove. Spines long and bristly or absent. Flowers mostly nocturnal, funnel-shaped or bell-shaped; flower tube with scales that are sometimes woolly or scaly in the axils. Fruit spherical, dry sometimes bristly, flesh red or purple.
The 3 commonly cultivated species are keyed out in the key.
Body generally growing extremely large.
About 9 species from Mexico.
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.
