Description

Key Characters:

Growth Form: Shrubs, erect to arching, clambering, or climbing, often sparingly branched, sometimes forming impenetrable thickets.

Stems: Stems segmented or unsegmented, green, greatly elongate, angled, 30–400[–700] × (4–)6–10 cm, ribs 3–5[–7], narrowly triangular to winglike, very prominent, 3–5 cm deep, less than 1 cm thick, rib crests undulate, areoles widely spaced, located next to sinuses, 2–5 cm apart along ribs, circular to oval, short woolly.

Roots: Roots diffuse, adventitious where arching stems touch soil.

Leaves: Leaves modified into spines. Spines [0–]4–10 per areole, diffusely spreading, brown or reddish [white, yellowish, or black], aging gray. Spines ± straight, acicular to subulate, terete (cylindrical) or somewhat flattened, longest spines 10–40[–70] mm, hard; radial spines [0–]6–8 per areole, 5–25 mm; central spines [0–]1–2[–4] per areole, 0–40 mm. Stipules absent.

Flowers: Flowers in lateral to terminal on stems 1 or more years old, at adaxial edge of areoles. Flowers bisexual (perfect), nocturnal, funnelform, [11–]14–20[–25] cm. Outer tepals green or purple tinged, lanceolate-linear, 3–5 × 1 cm; inner Tepals white, broadly linear to narrowly oblanceolate, 5–15 × 1–4 cm, margins entire or minutely denticulate. Stamens numerous. Ovary inferior, minutely scaly, spiny [spineless], with short wool; stigma lobes 10–15, white, to 12 mm.

Fruit: Fruits indehiscent or irregularly dehiscent longitudinally; red to red-purple; spheric; ovoid; ellipsoid; oblong; or pyriform; 30–80[–120] mm; fleshy or juicy [tough in A. columbianus]; scaly; spiny [or spineless]; scales deciduous; pulp red; floral remnant persistent. Seeds black; broadly obovoid; to 4.8 mm; smooth and shiny; seed coat cells flat.

Ploidy:

Habitat:

Elevation Range: