230 COMPOSITE. [CHAP. 



within a whorl of bract-leaves {involucre)^ there remains no 

 difficulty in comprehending the principal technical marks of 

 the Family. The Composites are distinguished from allied 

 families by — 



1. Their inflorescence in flower-heads. 



2. Their syngenesious anthers. 



3. Their inferior one-celled ovary, with a single erect 

 ovule. The Family is divided into three Tribes : — 



1. With the perfect or hermaphrodite florets regular 

 ( 7uhiUiflo)'ce). 



2. With the florets bilabiate {Labiatceflorce^ principally 

 South American). 



3. With all the florets ligulate {LigiiUflorcE. or dehor acece). 

 Sub-tribes are based upon the form of the style and of its 



divisions. 



The Family is represented in every quarter of the globe, 

 and in all zones : in the north temperate zone generally 

 by herbaceous or shrubby species ; in the tropics by large 

 trees, as well as herbs. 



Notwithstanding the enormous number of species in the 

 Family, reckoned at from 8,000 to 10,000, the proportion of 

 which any general use is made by man is comparatively 

 small. Many local species are used in medicine ; many 

 are bitter and aromatic, abounding in an etherial oil ; 

 and a considerable number are used as salad or pot-herbs 

 in temperate countries — amongst the rest, Lettuce (Lactuca) 

 and Artichoke {Cynara). Jerusalem Artichokes are the 

 tubers of a Ileliafithus, allied to the Sunflower {H. aiimius). 

 These are both American herbs, common everywhere in 

 Indian gardens : the seeds of the latter are edible, and yield 

 a valuable oil. Safilower [Carthaimis titictoritis) is cultivated 

 to some extent in India for its flowers, which yield a rose- 

 coloured dye. 



