METHODS OF POLLINATION. 



29 



same in each, the stamens and styles are of different 

 lengths, so that they have been called the "short- 

 styled," "mid-styled," and " long- styled " flowers. 

 These three different kinds are always on different 

 plants (Fig. 16). 



No experiments have been made with this plant, 

 but the celebrated Mr. Charles Darwin tried all sorts 



ly 



Fig. 16. — Trimorphic stamens and pistils of Ox'alis cer'nna. Ihe arrows 

 indicate tlie legitimate combinatious. 



of combinations of pollinations between three similar 

 kinds of flowers of an English plant of a very different 

 family. He found that the best way was to cross 

 each pistil with pollen from the stamens of the same 

 form, as shown by the arrows in the figure. When he 

 pollinated the tall styles with the shortest stamens, he 

 got little or no seed ; but by pollinating the mid-styled 

 form by either, he got a certain amount. Moreover, of 



