CACTACEAE. 293 



3. HYLOCEREUS (Berger) Britton & Rose, Contr. U. S. Xat. Herb. 12: 428. 



1909. 



Climbing or trailing cacti, with 3-winged or 3-angled, mostly stout stems 

 and branches emitting aerial roots, but bearing no leaves, the areoles borne 

 on the wings or angles and armed with few or several short spines. Flowers 

 nocturnal, very large, regular, the ovary and tube bearing large, ovate to 

 lineardanceolate scales, usually without spines or hairs, the perianth-segments 

 numerous, linear or narrowly lanceolate, widely spreading, the outer green, 

 the inner mostly bright white. Stamens very many. Fruit a scaly berry, not 

 spiny nor bristly. [Greek, forest-eereus.] About 20 species, natives of tropi- 

 cal America. Type species: Cereus triangularis L. 



1. Hylocereus undatus (Haw.) Britton & Rose; Britton, Fl. Berm. 256. 1918. 



Cereus undatus Haw. Phil. Mag. 7: 110. 1830. 



Cereus tricostatus Gosselin, Bull. Soc. Bot. France 54: 664. 1907. 



Stems stout, fleshy, glabrous, sometimes 7 m. long, often climbing on 

 trees, the branches 3-12 dm. long, green, 3-winged, the wings flat, 1-2.5 cm. 

 broad, coarsely crenate, their margins with a narrow horny border; spines 

 2-5 at each areole, brownish, 34 mm. long; flowers about 3 dm. long, the 

 tube about 3 cm. thick, rather shorter than the limb, bearing several linear- 

 lanceolate scales 3-8 cm. long; ovary 2.5-5 cm. long, bearing several ovate 

 acute scales 2.5 cm. long or less; style stout, about as long as the stamens; 

 berry oblong, red, pulpy, about 8 cm. long, covered with ovate scales. 



On trees and walls, spontaneous or persistent after cultivation. New Provi- 

 dence : Bermuda : Florida : the West Indies ; continental tropical America : native 

 of Mexico. Has been confused with Cereus triangularis L., of Jamaica. Night- 



BLOOMIXG CEREIS. 



4. SELENICEREUS (Berger) Britton & Rose, Contr. U. S. Xat. Herb. 12: 



429. 1909. 



Climbing or trailing, vine-like cacti, the joints several-ribbed, fluted or 

 angled, giving off aerial roots, the large funnel-form flowers nocturnal ; the 

 stem-areoles bearing conic or acieular spines, but no leaves. Ovary and flower- 

 tube bearing small scales, usually with long hairs and bristles or spines in 

 their axils. Perianth segments numerous, narrow, spreading or recurved, the 

 inner white. Stamens numerous. Fruit a globose or ovoid berry, usually 

 large, bearing clusters of deciduous spines. [Greek, moon-cereus.] About 

 14 species, natives of tropical America. Type species: Cactus grandiflorus L. 



Stems fluted: spines about 2 mm. long, shorter than the wool. 1. S. Bocckmani. 

 Stems 4-0>-angled, or ribbed ; spines G-8 mm. long, much longer 

 than the wool. 2. 8. grandiflorus. 



1. Selenicereus Boeckmanni (Otto) Britton & Rose, Contr. Nat. Herb. 12: 429. 

 19, 



Cereus Boeclcmanni Otto; Salm-Dyck, Cact. Hort. Dyck. 1849: 217. 1850. 



Stems light green, 1-2 cm. thick, several-ribbed or angled. Spines 3-6 at 

 the areoles, subconie, about 2 mm. long, brownish or yellowish; flowers about 

 3 dm. long; outer perianth-segments and Bcalee of the flower-tube linear, 

 brown or brownish; inner perianth-segments oblanceolate, about 10 cm. long 



