Flowers. 



^59 



Fig. 83. 



IV, a crowded cyme or fascicle ; x, a corymb ; 



y, an umbel. 



of a corymb, whose older flowers differ from those of a 

 raceme in having their pedicels elongated so that a some- 

 what flat-topped flower cluster is produced, y stands for 

 an umbel, having the 

 pedicels of nearly equal 

 length, and inserted at 

 about the same height 

 on the common axis. 

 2c represents a head of 

 the corriposite type, and 

 t a head of the clover 

 type with the receptacle 

 much exaggerated. 



The raceme, spike, 

 corymb, umbel, and head 

 are called indeterminate ; 

 they have this feature in common, that the older flowers 

 are at the base or periphery, and the younger flowers are 

 at the apex or center of the inflorescence. 



In another type of inflorescence known as the cyme {v 

 and w) the terminal or central flower is the oldest. This 

 sort of inflorescence is termed determinate, since the com- 

 mon axis is not indefinite in elongation as in the raceme 

 and spike. A compact cyme like that of the Sweet William 

 is called -a. fascicle, and one that is still more compact so as 

 to simulate a head is termed a glomerule. 



127. Tie paper bags over flowers, so that neither wind 

 nor insects can disturb them, and note whether they are 

 able to achieve self-fertilization. 



128. Before the stamens have discharged their pollen, 

 remove them from a flower, and then by means of a camel's 

 hair brush transfer to the stigma pollen from a flower of 

 another plant of the same kind. Tie a bag over the flower 



