13. Epiphyllum Haworth, Syn. Pl. Succ. 197. 1812.
Climbing cactus [Greek epi, upon, and phyllon, a leaf, referring to flowers borne on leaves, actually phylloclades, leaflike stems]
Michael W. Hawkes
Shrubs, epiphytic or rarely epipetric, erect to pendent, many branched. Roots diffuse or adventitious along stems. Stems segmented, green, segments leaflike, narrowly elongate-oblanceolate, terete or 3-angled in narrow proximal portion, broadly flattened and bladelike distally, with prominent midvein-like axis, [30-]50-120+[-500] × [1.5-]4-5[-12+] cm, glabrous; ribs 2 or, on proximal portion and on juvenile stems, 3, rib margins (crests) crenate-undulate to shallow lobed [serrate to pinnatifid in other species]; areoles only in sinuses along rib margins (ca. 2-7 cm apart along rib), circular, woolly, stiff spines absent, sometimes fine, hairlike bristles present; areolar glands absent; cortex and pith mucilaginous. Spines usually absent from adult stems, present and slender on terete and juvenile stems. Flowers nocturnal [diurnal in 2 species], lateral on stem in marginal areoles, with long tube, salverform to funnelform, 8-38 cm; flower tube straight or strongly curved to 90°; outer tepals greenish [to yellow, white, or dull red] often tinged with red, 3-10 cm, margins entire; inner tepals white [to yellow], 3-10 cm, margins entire; ovary scaly, spineless, spiny, or with bristles or hairlike spines; scales small; stigma lobes 8-21, white, extending beyond stamens, ca. 10 mm. Fruits dehiscent along 1 side when mature, light green, red, or purple, smooth [to ridged or angular], ellipsoid to ovoid, [20-]40-100 × 20-50 mm, fleshy, spineless, spiny, or with bristles or hairlike spines; pulp white or slightly pinkish; floral remnant persistent. Seeds black, reniform, 2-3 × 1-2.5 mm; testa cells shiny or dull when minutely pitted. x = 11.
Species 19 (1 in the flora): introduced; tropical regions of s Mexico, West Indies, Central America, n and c South America.
The spineless, leaflike stems of this epiphytic genus make it easy to overlook as a member of Cactaceae. The usually white, nocturnal flowers with long, thin flower tubes, copious nectar, and strong fragrance suggest hawkmoth pollinators for most species.
Kimnach, M. 1964. Epiphyllum phyllanthus. Cact. Succ. J. (Los Angeles) 36: 105-115.