THE FLOWEE. 



29 



vertically, being at the same time broadened, and having the flowers more 

 or less thickly crowded together upon a common receptacle, which, in fact, 

 the depressed primary axis becomes. Here the outer bracts, commonly 

 numerous, constitute the involucre, and the inner ones — that is, those 

 about the individual flowers— are reduced to chaffy scales or bristles. 



Fig. 46. — Staminate catkin of willow. 



Fig. 47. — Pistillate catkin of willow. 



In all these forms of inflorescence the lower or outer flowers expand 

 first, and the upper or inner last. There is, therefore, a movement from 

 the circumference toward the centre, and hence the inflorescence is 

 termed centripetal. 



Fig. 49. — Vertical section of same. 



Fig. 48.— A head (compound flower). 



Determinate inflorescence is much simpler and presents fewer 

 different forms. It comprises the cyme, fascicle, and glomerule. 



A cyme is commonly a flat-topped flower-cluster, like a corymb, only 

 it is produced in a different manner (Fig. 50). It presents several different 

 forms. 



