CACTUS OR SUCCULENT HOUSE 125 



The species of Phyllocactus are usually grown grafted upon 

 the stems of other plants, such as Opuntia. The practice is 

 not new. Epiphyllum truncatum was grafted on Pereskia 

 aatleata stock at Oxford, circ. 1834-7. 



Belonging to quite a different family are the Euphorbias or 

 Spurge-cactuses, the leafless forms of which resemble the 

 True Cactus, but are readily distinguishable by the milky 

 'juice which runs freely from the smallest wound. This juice is 

 so exceedingly poisonous that it is used in the preparation of 

 poisoned arrows by certain S. African tribes. 



The fine large Euphorbia arborea in the middle of the 

 house is now perhaps the oldest green-house plant in the 

 Garden. 



The following are the most noteworthy of the Cacti which 

 have been added to the collection or have flowered within 

 recent years : 



Cactus peacockii Echinocactus ottonis, var. tor- 



Cereus baumanni tuosus 



bridgesii pfeifferi 



formosus williamsii 



jamacaru Epiphyllum gartneri 



labouretii Euphorbia Caput-medusae 



martianus colletioides 



,, nycticalus meloformis,var. cor- 



quisco deroyii 



schelhasii Mamillaria castaneoides, var. 



smithii cristata 



tephracanthus crassispina 



tweediei ,. crinita 



Echinocactus capricornis gracilis, var. pul- 



corynodes chella 



cylindraceus, var. haageana 



longispinis heyderi 



,, grusonii ,, kleinii 



horridus (?) lactescens 



lecontei ,, longimamma 



myriostigma nicholsonii 



