Chapter XI. 

 PILOCEREUS. 



ONE of the most striking plants in this order is the ** Old Man 

 Cactus," Pilocereus senilis, the only member of this genus that has 

 become common in English gardens, though more than a dozen 

 species are to be found in botanical collections. Stem tall, erect, 

 thick, simple or branched, fleshy, ridged ; the ridges regular, 

 slightly tubercled, and placed closely together. Tubercles generally 

 hairy, with bunches of short spines ; hairs long and white, especially 

 about the apex of the stem. Flowers on the extreme top of the 

 matured stems, arranged in a cluster as in the Melon Cactus, small, 

 tubular, with a disagreeable odour, like that of boiled cabbage. 

 Fruit fleshy, round, persistent, usually red when ripe. Natives of 

 tropical America, in rocky gorges or on steep declivities of moun- 

 tainous regions. 



Cultivation. 



These plants require tropical conditions and all the sunlight 

 possible. In winter they may be kept quite dry, in a temperature 

 of about 60 deg., rising to 65 or 70 deg. in the day. In March 

 they should be repotted in a good, loamy soil with ample drainage. 

 Should the hairs become soiled or dusty, the stems may be laid 

 on their sides and syringed with a mixture of soft soap and warm 

 water to give them the white appearance to which the plants owe 

 their attractiveness. 



P. Houlletianus. 



Stem robust, glaucous-green ; ridges about eight, broad 

 prominent, obscurely tubercled ; spines in bundles of nine 

 radiating straight, less than 1 inch long, and pale yellow, those on 

 the top intermingled with long, white hairs, often matted together 

 like an unkempt head. Flowers funnel-shaped, borne in a cluster on 

 the summit of the plant ; ovary short and scaly ; petals joined at the 

 base, and coloured a rosy-purple, dashed with yellow ; stamens 

 white. Fruit globose, as large as a plum, cherry-red. The pulp 

 is bright crimson, and contains a few brownish seeds. 



