The World Flora Online

ACANTHOCEREUS (Engelm. ex A. Berger) Britton & Rose

Acanthocereus tetragonus (L.) Hummelinck, Succulenta (Leeuwarden) 20: 165. 1938; Cactus tetragonus L.; A. pentagonus (L.) Britton & Rose.

Plantas erectas o arqueadas, hasta 6 m de largo, frecuentemente formando matorrales; tallos 3–8 cm de grueso, costillas 3 (–5), cortamente crenadas, delgadas; espinas grises, aciculares a subuladas, las radiales 5–10, 3–35 mm de largo, las centrales 1–3 (–4), 1–7 cm de largo, raramente más cortas, la longitud muy variable en la misma planta. Flores regulares, 18–25 cm de largo y ca 10 cm de diámetro, nocturnas; tubo receptacular 14–18 cm de largo, aréolas distantes con escamas y tricomas cafés y a veces 1–2 espinas aciculares de 2–4 mm de largo; partes sepaloides del perianto linear-lanceoladas, 40–80 mm de largo y 5–10 mm de ancho, verde pálidas con márgenes blanquecinos o rojizos; partes petaloides del perianto 4–5 cm de largo y 0.8–1 cm de ancho, blancas o verdosas; ovario 1.5–2.5 cm de largo, aréolas con escamas y tricomas cafés y a veces 1–5 espinas aciculares de 2–13 mm de largo, estilo 15–20 cm de largo, lobos del estigma 10–12, 1–1.5 cm de largo. Frutos globosos, 5–9 cm de largo y 4–8 cm de grueso, carnosos, rojos, abriéndose; semillas subreniformes, 5 mm de largo y 3 mm de grueso, negras, lustrosas.

Común en bosques secos o espinosos, zona pacífica; 0–700 m; fl jun–oct, fr jul–nov; Moreno 10402, Stevens 10004; Estados Unidos (Florida, Texas), México al norte de Colombia y Venezuela. Las plantas con espinas de hasta 5 mm de largo, han sido segregadas como A. subinermis Britton & Rose, si bien la serie de variaciones parece ser continua. De otro modo las plantas no se pueden diferenciar. Un género con ca 5 especies distribuido desde Estados Unidos hasta Sudamérica pero mayormente en México y Centroamérica. Las frutas se usan para refrescos. "Pitahaya".

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Succulent erect or clambering shrubs; stems phylloid and jointed, the joints elongate, rooting adventitiously at the tips, 3- to 5-angled, the areoles marginal on the angles, shortly pubescent and prominently spiny. Leaves very inconspicuous, acicular and fugacious or apparently wholly lacking. Flowers nocturnal, sessile, borne singly at the areoles; perianth large, subsalverform, with an elongate tube, the segments very numerous, the outer progressively shorter and narrower than the inner, widely spreading, the tube bearing several minute caducous bracts and prominent pubescent and spiny areoles; stamens very numerous, the filaments somewhat shorter than the perianth, united at progressively deeper levels to the hypanthium; ovary cylindric-ovoid, the areoles numerous and crowded, pubescent and spiny; style filiform, terete, somewhat shorter than the outer and upper stamens. Fruit a fleshy berry with numerous seeds.

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Shrubs, erect to arching, clambering, or climbing, often sparingly branched, sometimes forming impenetrable thickets. Roots diffuse, adventitious where arching stems touch soil. 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. Spines [0-]4-10 per areole, diffusely spreading, brown or reddish [white, yellowish, or black], aging gray, ± straight, acicular to subulate, terete 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. Flowers nocturnal, lateral to terminal on stems 1 or more years old, at adaxial edge of areoles, 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; ovary minutely scaly, spiny [spineless], with short wool; stigma lobes 10-15, white, to 12 mm. 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; testa cells flat. x = 11.

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shrub

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SELECTED REFERENCE

Hunt, D. R. 1991. Acanthocereus. Bradleya 9: 82-83.

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