802 



THE BOOK OF GARDENING. 



Pilocereus. — This genus is chiefly remarkable for P. senilis, 

 the Old Man Cactus (Fig. 540), but there are also several other 



curious and interesting 

 species. They have 

 erect stems, sometimes 

 branched, and the 

 flowers, which have 

 an unpleasant odour, 

 are produced on top 

 of the matured stems. 

 P. Houlletianus has 

 glaucous stems, broad 

 ridges, and spines 

 mingled with long 

 cottony - white hairs. 

 The flowers, which 

 are funnel-shaped, are 

 borne in clusters ; 

 colour, rose-purple and 

 yellow. Fruit large and 

 bright red. P. senilis 

 will reach a height of 

 25ft. On the upper 

 portion it has a 

 number of long silky 

 white hairs, giving it 

 the appearance of 

 an old man's head : 

 hence the above 

 common name. P. 

 Brunnowianus, 

 P. Celsianus, and 

 P. Hoppenstedti, are three sorts also worth growing. 



Rhipsalis. — These are amongst the most peculiar of the 

 Cacti, some having thin willow-like stems, while the stems of 

 others are flattened and leaf-like. Sorts : R. Cassytha, R. Houlletii, 

 R. paradoxa, R. crispata, and R. funalis (Fig. 541). 

 R. Cassytha (Mistletoe Cactus) is of a pendent habit, with 

 numerous branches and branchlets, the latter being no thicker 

 than whipcord; the berries are white, like Mistletoe. R. commune 

 has a freely-branching, straggling stem, and white and purple 

 flowers ; this plant is very suitable for baskets. R. crispata has 

 flat, jointed branches, resembling an Epiphyllum ; the flowers 

 are small and white, as are the fruits. R. funalis has 

 straggling stems and numerous glaucous, thin branches ; the 

 flowers are white. Other kinds are R. Knightii, R. paradoxa, 

 R. salicornoides, R. myosurus, R. penduliflora, and R. sar- 

 mentacea. 



Fig. 540. — Pilocereus senilis. 



