Armatocereus Backeb.

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: Thompson, A, ; Forbes, S.; Spencer, R. (1997). Cactaceae. In: Spencer, R.. 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.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Caryophyllanae
order      Caryophyllales
family       Cactaceae