430 EUPHORBIACE^. [part ii. 



involucre, b the female flower, and c the male 

 ones. The fruit (Jig. 145) consists of three 



Fig. 144.— Elphorbia. Fig. 145.— Fruit of 



Euphorbia. 



carpels, each containing a single seed, which 

 divide with elasticity when the seeds are ripe. 

 All the plants belonging to this order have a 

 milky, glutinous juice when young, which in 

 some genera becomes solid when exposed to 

 the air. This is particularly the case with 

 Siphonia Hevea, a Brazilian tree, the sap of 

 which yields the Indian rubber used for Mac- 

 intosh cloaks, &c.; it being more suitable for 

 that purpose than the caoutchouc yielded by 

 the Ficus elastica^ which is the true Indian Rub- 

 ber. The principal other genera belonging to 

 this order are the Box (Buxus), the tree kind 

 of which yields the wood used for wood-engrav- 

 ing, and the dwarf variety is employed as edging 

 for gardens ; Croton, an annual species of which 

 {Croton Tiglium) yields the celebrated Croton 

 oil; the Cassava (Jatropha Manihot)^ which 

 though poisonous in a raw state, becomes the 

 wholesome food called tapioca, when properly 



