PILOCEREUS. 



71 



P. senilis. 



This is the Old Man Cactus (P.'g. 34). Stem attaining a height 

 of 25 feet, with a diameter of about 1 foot ; ridges from twenty-five to 

 thirty on plants 4 feet high ; the furrows mere slits, whilst the tufts 

 of thin, straight spines, 1 inch long, which crown each of the many 

 tubercles into which the ridges are divided, give the young stems a 

 brushy appearance. Aboirt the upper portion of the stem, and 

 especially upon the extreme top, are numerous white, wiry hairs, G 



Pig. 34. Pilocereus senilis. 



inches or more long, and gathered sometimes into locks. To this 

 character the plant owes its name of Old-Man Cactus ; but, by a 

 curious inversion of what obtains in the human kind, old plants are 

 less conspicuous by their white hairs than the younger ones. Some 

 years ago there were three fine stems of this Cactus among the culti- 

 vated plants at Kew. the highest of which measured 18 V feet. Ther 



