COMPOSITE TRIBE ; DAHLIA. ' , 463 



Mexico ; and in its wild state it is a bushy herbaceous plant, 

 growing to the height of about seven or eight feet, with flowers 

 by no means remarkable for their beauty. It was introduced 

 into this country soon after the commencement of the present 

 century. 



633. The foregoing general account of the structure of this 

 remarkable order, is all that the limits of the present Treatise 

 permit to be given ; a few remarks will now be added on its 

 geographical distribution, its properties, and uses. The order 

 attains its greatest development, in regard to the size of the 

 species it contains, in the neighbourhood of the Equator ; for 

 whilst, in the temperate parts of the world, Compositae are 

 entirely herbaceous plants, those of Chili are bushes, and those 

 of St. Helena are trees, almost the only ones native to the 

 island. But in regard to number, it would seem that they 

 predominate rather in temperate regions, especially of the northern 

 hemisphere, where they are considered as forming about one-sixth 

 of the whole vegetation. In Britain, about 140 species of them 

 may be reckoned, constituting about one-tenth of the whole 

 number of native flowering-plants. In France they are estimated 

 at about one-seventh, and in Germany at one-eighth ; whilst in 

 Lapland they are only one-fifteenth. In Sicily they are said to 

 constitute more than half; and nearly the same proportion is 

 found in some parts of North America. In the north of New 

 Holland, on the other hand, the proportion is not more than 

 one-sixteenth ; and of a collection of plants formed upon the 

 western coast of Africa, it did not exceed one-twenty-third. The 

 Cichoraceae have been ascertained to be more abundant in cold 

 regions, and the Corymbiferae in hotter ones. 



634. In considering the properties of the order /t will be 

 necessary to advert separately to each of its subdivisions. The 

 Cichoracece as already stated, possess a milky juice, which is 

 bitter and astringent, as well as narcotic. These properties are 

 strongly manifested in the Lactuca mrosa or strong-scented 

 Lettuce ; for the juice, when concentrated, has narcotic effects 

 sufficiently powerful to enable it to be used for the purpose of 

 procuring sleep, instead of opium ; and the cells or vessels in 



