148 BOTANY. 



order. The coexistence of the two characters synge- 

 nesious anthers and a flower-head is sufficient to iden- 

 tify any plant of the order compositae, or, what is the same 

 thing, to characterize it; but these, added to the other 

 characters that invariably accompany them, are the char- 

 acters Of the order. 



Though all composite plants are alike in certain par- 

 ticulars, called their ordinal characters^ they differ much 

 among themselves in other respects. Though they all 

 have bitter properties, yet some are tonic, some acrid, and 

 some narcotic. One group will have milky juice, another 

 will be watery and aromatic, or mucilaginous,, or gummy, 

 or oily. In respect to the structure of flower-heads, you 

 have already found the dandelion, with all its florets, per- 

 fect and ligulate ; you found the thistle with perfect tubu- 

 lar florets ; you found the marigold with ? ligulate disk 

 florets, and $ tubular ray florets; the daisy with ? ray 

 florets, and $ disk florets. By referring to this order in 

 the Flora, you will find that these differences serve in ar- 

 ranging this vast family into sub-families, and these sub- 

 families are again separated into smaller groups by still 

 other characters. Differences in the involucre, and in the 

 conditions of the inferior fruit, serve to separate them into 

 what are called genera (see Flora, page 242), and then the 

 species of a genus are found to differ still further in the 

 characters of leaf and stem, in size, color, etc. 



In Order VIII of Chart II, illustrating the Compositae, 

 the characters of the dandelion, thistle, marigold, bache- 

 lor's-button, and globe amaranth, are given ; those of the 

 dandelion and thistle are presented in full detail, and 

 much enlarged. 



