70 MISSOURI BOTANICAL GARDEN. 



They are all columnar, curious-looking plants and general 



favorites of cactus growers, but fine specimens are never- 

 theless extremely rare. 



According to their descriptions, the following species 

 form this subgenus : 



Cereus (Pilocereus) chrysacanthus (Web.) A. Berg. 1. c. 178. 



Mexico. 



C. (Pilocereus) exerens Link. 1. c. 184. — Brazil. 



C. (Pilocereus) Hermentianus Monv. 1. c. 18G. Nachtr. 6G. — Haiti. 



C. (Pilocereus ?) Iloppenstedtii (Web.) A. Berg. 1. c. 177. — Mexico. 



C. (Pilocereus) Houlletu (Lem.) A. Berg. 1. c. 182. — Mexico. 



C. (Pilocereus) lanuginosus Mill. 1. c. 183. — West Indies. 



C. (Pilocereus) Boyeni Haw. 1. c. 181. — West Indies. 



C. (Pilocereus) strictus P. DC. 1. c. 188. — West Indies, South America. 



C. (Pilocereus) Ulei (K. Sch.) A. Berg. 1. c. Nachtr. G6. — Haiti. 



Cereus Iloppenstedtii A, Berg, was formerly included 

 by Schumann in Cephalocereus. I have never seen its 

 flowers. The plant resembles Cereus senilis DC. much 

 more closely than any Pilocereus. 



X. PIPTANTHOCEREUS A. Berg. 



Flowers naked, with a very few minute scales on the somewhat 

 elongated ovary and scarcely any wool or hairs in their axils; tube 

 elongated, funnel-shaped with a few remote obtuse scales, often slightly 

 furrowed; sepaloid perianth leaves obtuse, the following acute; petaloid 

 perianth leaves broader, acute, mostly white; stamens numerous in 

 two groups; style as long or longer, with numerous stigmata; flowers 

 large and showy, nocturnal, soon falling off a little above the ovary; 

 style persistent. Fruit oblong or globose, naked, reddish, at the top 

 deeply umbilicate, the remaining style bent downwards; pulp white; 

 seeds numerous, with opaque, black, finely punctate testa.— Plate 5, 6. 

 7,f.l-4. 



Arborescent or frutescent species, natives of Atlantic 

 tropical America from Argentina to the West Indies. 



This is a very natural and easily recognizable subgenus. 

 The perianths fall off, soon after flowering, a little above 

 the ovary, as neatly as if they had been cut off. The 

 style remains. The fruit is naked. 





