CHAP, t.] CACTACEtE. 371 



j)hyllum phylantlioides^ has thin leaf-Hke stems 

 with beautiful pale rose-coloured flowers. C. 

 Jenkinsonii is a hybrid between the last two 

 species. C. truncatus is another well-known 

 species. Opuntia has stems consisting of round, 

 flat, leaf-Uke bodies, united together by joints, 

 and generally covered with tufts of spines. The 

 most remarkable species are O. communis^ the 

 Prickly Pear, grown to a great extent in the 

 South of Europe, and also in Brazil, as hedges, 

 the fruit of which is very good to eat ; O. Tuna^ 

 the Indian Fig, common in South America, and 

 much cultivated there, both as a hedge plant 

 and for its fruit ; and O. cochinillifera^ the 

 Nopal-tree, very much cultivated in Mexico 

 and South America, for the cochineal insect, 

 which feeds upon it. Rhipsalis has slender 

 cylindrical jointed stems, which look like sam- 

 phire. All these genera have only leaves when 

 quite young, and as soon as the plants begin to 

 grow, the leaves fall off. Pereskia, however, 

 is a genus belonging to this order which has 

 leaves like ordinary plants, which it retains 

 during the whole period of its existence. The 

 principal species are P. aculeata, the Barbadoes 

 Gooseberry, and P. Bleo, which has beautiful 

 rose-coloured flowers. 



B b2 



