196 



the; cactaceae. 



3 soon dropped out. In some cases- the joints are nearly terete at base, or in cultivation 

 develop long terminal shoots which are nearly terete. 



This species was first collected by R. H. Peters in 1907. It was again collected by Mrs. 

 T. D. A. Cockerell at Ouirigoa in 191 2, who sent living plants to Washington which flowered 

 September 27, 191 7, anjd in 1920 Harry Johnson sent us living specimens from Guate- 

 mala. In 1916 Francis J. Dyer sent from Honduras what seems to be this species. 



Illustration: Contr. U. S. Nat. Herb. 16: pi. 69, as Hylocereus minutiflorus . 



Plate xxxii, figure 2, shows a flowering branch of the type specimen, which was col- 

 lected by R. H. Peters in Guatemala in 1907. Figure 272 shows a flowering joint of the type 

 specimen, photographed in Washington. 



Fig. 272. — Wilmattea minutiflora. 



3. SELENICEREUS (Berger) Britton and Rose, Contr. U. S. Nat. Herb. 12: 429. 1909. 



Slender, trailing, climbing or clambering, elongated cacti, the joints ribbed or angled, irregu- 

 larly giving off aerial roots; areoles small, sometimes elevated on small knobs, bearing small spines 

 or in one species spineless ; flowers large, often very large, nocturnal ; flower- tube elongated, somewhat 

 curved; scales of ovary and flower- tube small, usually with long felt, hairs and bristles in their axils; 

 upper scales and outer perianth-segments similar, narrow, greenish, brownish, or orange; inner 

 perianth-segments broad, white, usually entire; filaments elongate, weak, numerous, in two clusters 

 distinctly separated, one cluster forming a circle at top of flower-tube, the other scattered over the 

 ong, slender throat; style elongated, thick, often hollow; stigma-lobes slender, numerous, entire; 

 ruit large, reddish, covered with clusters of deciduous spines, bristles, and hairs. 



Type species: Cactus grandiflorus Linnaeus. 



The name is from the Greek and signifies moon-cereus, the plants being night-blooming. 



All the species are clambering vines with aerial roots, and in the tropics often reach the 

 tops of high trees ; where there are no trees or shrubs, they trail over rocks and walls. Most 

 of them have very large flowers ; in fact, one of the largest flowered species of the family (S. 

 macdonaldiae) belongs here. Several of the species, such as 5. hamatus, S. grandiflorus, 

 S. macdonaldiae, and 5. pteranthus (better known as Cereus nycticalus), have long been 

 favorites with amateurs. In our studies of the genus we have had several hundred growing 

 plants under observation, representing all the species, and specimens of all have bloomed. 

 The species of the genus range from southern Texas through eastern Mexico, Central 

 America, the West Indies and along the northern coast of South America, while one species 

 has been reported from Argentina. Sixteen species are here recognized. 



