EUPHORBIALES. 485 



of various African and Indian species of Euphorbia, Cascarilla Bark and 

 Melambo Bark from species of Croton in tropical America, are more or 

 less known iu pharmacy. 



Hevea Guianeims and other species of the genus, natives of the 

 northern part of South America, furnish the important substance 

 Caoutchouc, or India Rubber. The trees are from fifteen to thirty 

 metres in height (50 to 100 ft.), and bear trifoliate leaves resembling 

 those of the Scarlet-runner bean in size and shape. The natives make 

 incisions into the trees, from which the milky juice exudes, and this 

 evaporated constitutes the crude Caoutchouc. By heating the crude 

 product with sulphur it is hardened, and is then known as " Vulcan- 

 ized rubber." 



Exccecaria sebifera, the Tallow tree of China, now cultivated in the 

 warmer parts of America, has its seeds coated with a white greasy sub- 

 stance, which yields a valuable tallow from which candles are made. 



Aleurites Moluccana, the Candle Nut tree of India and the Pacific 

 islands, produces a large oily fruit, which is itself burned and used as 

 a candle, or from which a valuable oil is extracted. 



The most valuable timber of the order is furnished by Buxus semper- 

 virens, the Box tree of Europe and Asia. It is a small evergreen 

 tree, with a very hard yellowish wood, invaluable in wood engraving, 

 the manufacture of mathematical instruments, etc. Our chief supply 

 comes from the Mediterranean ports. A dwarf variety of this species 

 is used for bordering garden walks. 



African Teak, a very heavy and hard wood from Africa, is supposed 

 to be derived from Oldfieldia Africana, which has been doubtfully re- 

 ferred to this order. 



Among the plants grown for ornament are many species of Euphor- 

 bia, an immense genus of 700 species, distributed very widely ; in 

 Africa they assume a Cactus-like aspect, having thick succulent stems. 

 These and many other species are to be found in conservatories. The 

 curious Xylophytta, with flat leaf-like branches, bearing flowers upon 

 their edges, is also common. 



The Sand Box tree of tropical America bears a curious many-celled 

 fruit which when dry explodes with a loud report. 



The juice of many of the species is poisonous when dropped upon the 

 ekin, or into a wound. The Manchineel tree (Hippomane Mancinelld) 

 of South Florida and the West Indies is extremely poisonous, but many 

 of the stories told of it are fabulous. 



Zebra Poison is the name applied to Euphorbia arborea ; branches of 

 it placed- in water render it sufficiently poisonous to kill the animals 

 which drink it. 



575. Cohort VII. Amentales. Woody plants, with di- 

 clinous flowers, mostly in catkins ; the one or two-celled 

 ovary superior, and the seeds with no endosperm. 



