Presumed to be derived from Vaccinium myrtillus, referring to the similarity of the fruits of these plants.
Body becoming tree-like or shrubby, erect with numerous branches. Stems with few ribs, spiny. Flowers diurnal, prolific (to 9 per areole), creamy white; stamens relatively few. Pericarpel with small scales that are woolly in the axils; flower tube short. Fruit small, spherical, fleshy, mostly reddish to purple.
Grown mostly is M. geometrizans (Mart.) Console from Mexico which grows to several metres tall with many stems which are bluish, to 10 cm wide with 5-6 ribs and well spaced areoles each with a single, blackish, large broad-based spine and reddish to grey radials.
Ribs 5-9; flowers small, scales slightly woolly.
4 species (or possibly varieties of a single species) from Mexico and Guatemala.
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.
