Plants climbing, scrambling, or epiphytic. Stems branched, usually 3-winged or -angled, margins often horny, often producing numerous aerial roots. Areoles spaced far apart in notches along wings or angles. Spines short or rarely absent. Leaves absent. Flowers usually nocturnal, white or rarely red, funnelform, large. Receptacle tube usually elongate, stout, with broad, leaflike scales. Stamens numerous, inserted in receptacle tube and perianth throat, shorter than perianth. Placentas parietal; stigmas numerous, sometimes 2-fid or flabellate. Fruit globose, ellipsoid, or ovoid, large, fleshy, spineless, with broad scales. Seeds numerous, ovate-reniform; testa glossy black, smooth or minutely spotted.
HYLOCEREUS (A. Berger) Britton & Rose
Trepadoras epífitas o terrestres; tallos triangulares o 3-angulados, produciendo raíces aéreas en todo su largo, costillas unduladas; aréolas con espinas cortas, frecuentemente cónicas, raramente sin espinas. Flores grandes, infundibuliformes, nocturnas o raramente diurnas; tubo receptacular con escamas foliáceas; partes del perianto blancas, raramente rojas; estambres numerosos, insertados en la garganta del tubo receptacular; ovario con escamas foliáceas. Frutos globosos u ovoides con escamas foliáceas, carnosos, rojos; semillas numerosas, ovado-reniformes, lustrosas, negras.
Un género con 6 a 8 especies mal definidas, nativas desde México hasta Venezuela, Perú y en las Antillas; 1 especie se ha colectado en Nicaragua y otra se espera encontrar. Los frutos son comestibles y frecuentemente usados en refrescos. "Pitahaya".
Shrubs, epiphytic, hemi-epiphytic, or epipetric, straggling, climbing, scandent, or pendent, irregularly many branched. Roots diffuse, often adventitious along stem internodes. Stems segmented, green, blue-green, gray-green, or somewhat whitish with wax; segments elongate, 3-winged or -angled, length highly variable, 10-500+ × [1-]4-7.5[-10] cm, distinctly narrowed proximally, glabrous; ribs (2-)3(-5), winglike to narrowly triangular in cross section, rib crests straight to undulate, crenate [toothed, notched, or lobed], often with a line of hard, brown to gray bark between areoles; areoles (10-)35-50 mm apart along ribs, oval, short woolly, sometimes subtended by minute, vestigial leaves at growing stem tip; areolar glands inconspicuous; cortex and pith mucilaginous. Spines 0-4[-8] per areole, whitish or yellowish to brownish [blackish or red, aging gray], acicular [awl-shaped or hairlike], straight, terete, generally short, 0-4[-10] mm, hard, bases sometimes conic or swollen, smooth, glabrous; radial and central spines not distinguishable. Flowers nocturnal, lateral to subterminal on 1+-year-old stems, at adaxial edges of areoles, long tubed, funnelform, [3-]25-29[-38] × [8-]15-25[-30] cm; outermost tepals often greenish, yellow, pink, or occasionally purplish red or white, 10-15 × 1-1.5 cm, margins entire; inner tepals white to cream [rarely pinkish or red], 10-15 × 1.5-2.5 cm, margins entire; ovary tuberculate [to smooth], scaly, spineless, usually without hairs or wool; scales triangular, broad, thick conspicuous, to 25 mm; stigma lobes to 24, white. Fruits irregularly dehiscent along 1 side, red [to purple or magenta], oblong to ovoid or spheric, [20-]50-125 × 40-120 mm, fleshy, spineless; pulp white; scales persistent, green, triangular, conspicuous, thick and fleshy, to 4+ cm; floral remnant often persistent. Seeds black, [elongate or] pyriform [to reniform], 2-3 mm, glossy; testa smooth or minutely textured. x = 11.
Succulent shrubby root-climbers, frequently epiphytic; stems phylloid and jointed, rooting adventitiously at the nodes, the joints elongate, usually 3-angled, the areoles marginal on the angles, shortly pubescent and with infrequent and inconspicuous spines. Leaves inconspicuous and fugacious or wholly lacking. Flowers nocturnal, sessile, borne singly at the areoles; perianth large, broadly in- fundibuliform, the segments very numerous, the outer progressively shorter and less petaloid than the inner, the tube rather broad and somewhat shorter than the seg- ments, bearing rather few conspicuous, persistent foliaceous bracts but without well-defined areoles; stamens very numerous, the filaments shorter than the peri- anth, united at progressively deeper levels to the hypanthium; ovary cylindric- ovoid, with few to numerous persistent accrescent foliaceous bracts but without well defined areoles; style filiform, somewhat longer than the stamens. Fruit a fleshy berry with numerous seeds.
|Night-blooming cereus [Greek hyle, forest, and Cereus, the genus from which this segregate was removed]|