I 86 THE CACTACEAE. 



We have referred here the 3 specimens collected by Dr. Rose in Ecuador although we 

 are not sure that these are even conspecific. They all grow in very diverse habitats; only 

 one was seen in flower. No. 22 116 was found growing closely appressed to the trunk of a tree 

 to which it was so tightly attached that it was with difficulty that specimens were obtained. 

 The locality was on the edge of the mangrove swamp near Guayaquil. In the same region 

 were seen other plants, presumably of the same species but these were clambering from tree 

 to tree high up in their tops and far out of reach. No. 23342 was in a very peculiar habitat 

 for a Hylocereus. It came from the edge of the Catamayo Valley, a hot semiarid region. 

 Its stems were very stout, almost woody, and were spread out all over the top of a small 

 tree. No flowers or fruit were seen and only a single plant was observed. The branches 

 were nearly 10 cm. broad and the brown spines were usually 4 in a cluster and nearly 1 cm. 

 long. On the other hand No. 23396 was found in a habitat very suitable for ^Hylocereus; 

 this was in a tree along a stream east of Portovelo in southern Ecuador ; the plant was 

 in flower but almost out of reach so that it was with difficulty we obtained a single flower. 

 The following brief notes are based on our field observations : 



Steins 3 -angled, whitish; flowers 31 cm. long, fragrant; outermost segments short, purple; 

 outer scales oblong, orange-red; inner perianth-segments white, tinged with pink; stamens yellow; 

 scales on the ovary oblong, acute, dull green, with purple margins. 



5a. Hylocereus venezuelensis sp. nov. (See Appendix, p. 226.) 



6. Hylocereus costaricensis (Weber) Britton and Rose, Contr. U. S. Nat. Herb. 12: 428. 1909. 



Cereus trigonus costaricensis Weber, Bull. Mus. Hist. Nat. Paris 8: 457. 1902. 



Vigorous vines, perhaps the stoutest of the genus, sometimes 10 cm. broad, normally 3-angled, 

 at first green or purplish, but soon becoming white and afterwards green or gray; ribs or wings com- 

 paratively thin although in age becoming more turgid; margin rather variable, either straight or 

 somewhat undulate, obtuse, never horny; spines 2 to 4, short, rather stout, brownish, usually ac- 

 companied by two white hairs or bristles which finally drop off ; young flower-buds globular, purple ; 

 flowers 3 dm. long or more, strongly fragrant; outer perianth-segments narrow, more or less reddish, 

 especially the tips; inner perianth-segments pure white; stigma-lobes rather short, yellowish, entire; 

 ovary covered with closely set scales, these having deep purple margins; fruit scarlet, oblong, 10 

 cm. long. 



Fig. 262. — Ovary of Hylocereus costaricensis transformed into branch. X0.94. 



Type locality: Costa Rica. 



Distribution: Costa Rica. 



This species was originally described as a variety of Cereus trigonus, but it has much 

 stouter blue stems and is otherwise different. It grows well in cultivation and frequentlv 

 flowers. The very young areoles on the stem produce an abundance of nectar which runs 

 down the stem in large sticky drops, 

 reduced leaves from the lower areoles. 



Figure 262 represents an arrested flower transformed into a branch showing scales or 



