314 



FLOWERS 



family), the violets, and the mints, and these flowers 



generally do not set seed unless pollinated by bees. The 



natural distribution of 

 clover, for example, is 

 confined to those parts of 

 the world which are in- 

 habited by bees. 



The flower of Salvia il- 

 lustrates a structure favor- 

 able to pollination by 

 bees. This structure, or 

 one much Hke it, is quite 

 common among zygomor- 

 phic flowers. (Study Fig- 

 ure 133.) Salvia is a 

 member of the mint family. 

 It is grown commonly in 

 beds near houses and walls, 

 and is familiar on account 

 of its bright red flowers 

 which bloom in late Au- 

 gust and September. 



The snapdragon is an- 

 other cultivated flower 

 with a zygomorphic co- 

 rolla. It is usually tightly 

 closed and small insects 

 cannot enter it. But 

 when a bee alights upon 



the lower lip of the corolla, its weight depresses the lip 



and opens the flower. 

 The violet has a zygomorphic corolla and a spur. The 



Fig. 134. — An inflorescence of one of the 

 species of yucca. Note that the flowers 

 hang downward, thereby protecting 

 their inner parts from rain. 



