THE COMPOSITE FAMILY. 169 



crawling over the head, get dusted with pollen, which 

 finds its way on to the " stigmatic surface," on the upper 

 surface of the style-arms ; or else on those of other 

 heads to which the pollen-carrying insect may fly. 



Many florets manage to fertilize themselves. One 

 way is to keep the stigmas within the tube, but slightly 

 separating them there, so the pollen is applied directly 

 to them. This can easily be seen in the Groundsel. 

 Another way is for the style-arms to curl backwards, 

 so that the tips are plunged into the pollen brought 

 from below (Fig. 69). 



As a rule, there are many florets in one head ; but 

 in the genus Corym'hium, of which there are seven 

 species, the cylindrical involucre of very few bracts 

 contains a single floret. They also have a curious 

 silky root-stock with linear, grass-like leaves. 



General Descnption of the Comjjosite Family. 



Herhs, shruhs, or trees. 



Leaves — Various. 



Flowers — In heads within an involucre of bracts. 



Florets — With a superior pappus (calyx) or none ; 

 petals coherent, tubular, or ligulate, epigynous ; stamens, 

 5, upon the corolla, filaments free, but anthers coherent 

 (syngenesious). 



Fruit — Inferior achene, with or without a pappus. 



