DICOTYLEDONES-CALYCIFLOR^ 359 



Distribution and Numbers. — Chiefly natives of the northern 

 parts of Europe, Asia, and America. Many occur, however, in 

 the southern hemisphere. They are rare 

 in tropical regions except upon the raoun- ^i<*- mS- 



tains, vifhere they are by no means un- 

 common. There are about 1,400 species. 

 Properties and Uses. — Extremely 

 variable : thus, some are edible ; others 

 aromatic and carminative, and, in some 

 cases, stimulant and tonic, from the 

 presence of a volatile oil; some, again, 

 contain a narcotico-aorid juice, which 

 renders them more or less poisonous ; 

 while others are antispasmodic and 

 stimulant from the presence of a, more «y-lli9- Piowerofthecom- 



. .... mon Ivy {^I-Iedera Helix). 



or less icetid gum-resm, which is essen- 

 tially composed of gum, resin, and volatile oil. This oil in the 

 case of Asafoetida contains sulphur. 



Order 159. AkaliacEjE, the Ivy Order. — Character. — Trees, 

 shrubs, or herbs. Leames alternate, exstipulate. Flowers 

 generally in umbels or capitula, usually perfect or rarely uni- 

 sexual. Calyx more or less superior, entire or toothed. Petals 

 2, 4, 5, 10, deciduous, almost always valvate in sestivation or 

 rarely imbricate, generally distinct or rarely gamopetalous ; 

 occasionally wanting. Stamens corresponding in number to 

 the petals and alternate with them, or twice as many, inserted 

 on the outside of a disc which crowns the ovary ; anthers 

 introrse, versatile, with longitudinal dehiscence. Ovary more or 

 ■less inferior, usually with more than 2 cells, or very rarely 

 1-celled, crowned by a disc ; each cell with a solitary pendulous 

 anatropous ovule ; styles as many as the cells, sometimes 

 united ; stigmas simple. Fruit usually 3- or more-celled, succu- 

 lent or dry, each cell with 1 pendulous seed, with fleshy albumen. 



Diagnosis. — Closely allied to UmbeUiferse, from which it may 

 be distinguished by the valvate sestivation of the corolla ; and 

 by the fruit being usually 3- or more-celled, the carpels of which 

 do not separate when ripe from a carpophore. There is also a 

 greater tendency among Araliacese to form a woody stem than 

 in UmbeUiferae. 



Distribution and Numbers. — These plants are universally 

 distributed, being found in tropical, subtropical, temperate, 

 and the coldest regions. Illustrative Q-enera : — Panax, Linn. ; 

 Hedera, Linn. The order includes about 300 species. 



