Chapter XVI. 

 PERESKIA. 



THE Pereskias differ so markedly from all other kinds of Cacti, 

 that at first sight one can scarcely believe they are true Cacti, 

 closely related to Cereus and Epiphyllum. They have erect or 

 trailing stems and branches, and usually form dense, large bushes ; 

 the branches are woody and thin, and bear large, laurel-like leaves, 

 which remain on the plants several years so that they may be 

 termed evergreen. They have, however, the spine- cushions, the 

 tufts of woolly hair and stout spines, and the floral characters 

 which distinguish Cactacese from other orders ; they are also 

 succulent, the leaves and young branches being soft and fleshy. 

 They appear to have the same peculiar provision for enabling 

 them to bear long periods of drought without suffering that charac- 

 terises the plants of this order. The development of the spines in 

 Pereskia is different from what takes place in all other Cacti, in 

 which the spines are the stoutest and most numerous on the 

 younger parts of the plant, the older or woody parts being either 

 spineless, or much less spiny than when they were younger. Thus, 

 in Opuntia we find few or no spines on the old parts of the stems of 

 even such species as O. horrida, 0. nigricans, & c. In Echinocactus, 

 too, the spines about the base of old plants, if not entirely cast off, 

 are much fewer than on the upper part. In Pereskia the contrary 

 is the case. Taking as an example P. ac>deata, we find that it 

 has branches about as thick as a goose-quill, with ovate leaves, 

 at the base of which there is a pair of curved spines, J inch long, 

 and shaped like cats' claws. But when it gets old it has a stem 

 3 inches in diameter, and clothed down to the ground with cushions 

 of spines fixed firmly in the bark, each cushion composed of from 

 twenty to fifty spines, and each spine 1 inch or more in length. 

 From two to six new spines are developed in the centre of each 

 healthy cushion annually. It would be impossible for any animal 

 to climb an old stem of Pereskia. In P. Bleo the spines are 2 inches 

 long, and the clusters are much larger. 



The flowers of Pereskias are borne singly or in panicles, at the 

 ends of the young, ripened branches. In shape, each flower may 

 be compared to a single Rose, the petals being flat and spreading, 

 and the numerous stamens forming a compact cluster in the centre, 



