Latin armatus—armed.
Body large shrubby to tree-like. Stems more or less erect, cylindric, ribbed and constricted into segments. Ribs 3-13. Areoles felty, generally with spines. Flowers nocturnal, tubular (not flared towards the tip), white (rarely red). Fruit ovoid to round, fleshy, spiny.
Available as A. rauhii Backeb. from N Peru which has 10-13 ribs and carmine flowers; it can eventually grow to about 6 m tall. Closely related to Stenocereus.
Stems constricted into segments; flower mouth narrow.
About 10 species from Peru and Ecuador.
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.
