III.] COMPOSITE. 229 



The florets of the same flower-head may all be perfect 

 ( Venio?iia, Sonchns) ; or those of the disk may be perfect and 

 those of the ray pistillate {Zinnia), or the florets monoecious 

 {Calendula) ; or the outer florets may be neuter, or all the 

 florets of the flower-head may be unisexual and the heads 

 dioecious, as in the common Thistle of waste places {Carduus 

 arvensis). 



Fio. 142. Vertical section through flower-head of Sonchus. 



If all the florets of a flower-head be perfect, it is said to 

 be homogamous ; if some of them be imperfect, it is hetero- 

 gainous. 



Compare, also, the coinmo7i receptacle of Vernonia, or of 

 any common Blumea, with that of Zinnia. The latter has 

 numerous chaffy scales, or minute bracts, called pales, 

 amongst the florets, and the common receptacle is said to 

 be paleaceous ; the former are destitute of scales, and the 

 common receptacle is said to be 7iaked. 



The Composite Family is the largest in the vegetable 

 kingdom, and at the same time one of the best-defined and 

 most easily recognised. When once it is thoroughly under- 

 stood that the " flower-heads " are not simple flowers, but 

 heads of (usually numerous) independent florets enclosed 



