Latin melo—melon, referring to the body shape.
Body low-growing, mostly solitary and unbranched, compressed spherical to cylindrical, strongly ribbed, spiny. Body apex forming a distinctive dense, woolly, mostly bristly head (cephalium) which bears the flowers and fruits. Flowers small, tubular, red to pink, mostly buried in the head. Pericarpel and flower tube naked. Fruit fleshy, club-shaped.
A group in need of revision with the species intergrading. M. azureus Buining &Brederoo has white to pinkish fruit. M. brederooianus Buining. has sometimes been incorrectly named M. bahiensis (Britton & Rose) Luetzelb. M. matanzanus Leon from N Cuba has densely distributed orange-red bristles.
Flowers diurnal, arising from a pronounced terminal cephalium; flowers cylindrical; pericarpel of flower tube naked.
About 20-25 species from S America, C America and Caribbean.
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.
