430 



POLLINATION OF FLOWERS 



lodged on the prominent stigmas and thus produce the desired 



cross pollination. 



Closely related flowers often differ in their plan of pollination. 



The high mallow (a plant cultivated for its purplish flowers), 

 which has run wild to some extent, is ad- 

 mirably adapted to secure cross pollination, 

 since when its stamens are shedding pollen, 

 as in Fig. 329, B, the pistils are incapable of 

 receiving it, while when the pistils are ma- 

 ture, as in D, the stamens are quite withered. 

 In the common low mallow of our door- 

 yards and waysides insect pollination may 



FIG. 330. Stamens 

 and pistils of round- 



occur, but if it does not, the curling stigmas 



leafed mallow 



The stigmas curled fina % come in contact with the projecting 

 round among the sta- stamens and receive pollen from them, as is 



mens to admit of self . -,. , i TTI- OOA 



pollination. -After indicated in Fig. 330. 



Muiier 406. Movements of floral organs to aid in 



pollination. Besides the slow movements which the stamens 

 and pistil make in such cases as those of the Clerodendron and 



FIG. 331. Two flowers of common sage, one of them visited by a bee 

 After Lubbock 



the mallow, already described, the parts of the flower often 

 admit of considerable and rather quick movements that assist 

 the insect visitor to become dusted or smeared with pollen. 



