ADAPTATIONS FOR INTERCROSSING. 



221 



bud, straighten and project when the corolla opens : the stamens 

 remain straight, but the style proceeds to curve downward and 

 backward, as in Fig. 423. The anthers are now discharging 

 pollen : the stigmas are immature and closed. Fig. 424 repre- 

 sents the flower on the second day, the anthers effete, and the 

 filaments recurved and rolled up spirally ; while the style has 



taken the position of the filaments, and the two stigmas now 

 separated and receptive are in the very position of the anthers the 

 previous day. The entrance by which the proboscis of a butterfly 

 may reach the nectar at bottom is at the upper side of the orifice. 

 The flower cannot self-fertilize. A good-sized insect flying from 

 blossom to blossom, and plant to plant, must transport pollen 

 from the one to the stigma of the other. 



410. Proterandry abounds among common flowers. It is 

 conspicuous in Gentians and in nearly all that family. But, 

 while in Gentians the short style is immovable and erect, in 

 Sabbatia it is thrown strong!} 1 to one side, out of the wa} T of and 

 far below the stamens, the branches closed and often twisted, so 

 that the stigma is quite inaccessible until the stamens have shed 

 their pollen : then the style becomes erect, untwists, its two flat 

 branches separate, and expose the stigmatic surface of their inner 

 face in the place which the anthers occupied. In Sabbatia 

 angularis, Lester F. Ward 1 observed that the anthers of freshly 



1 In Meehan's Gardeners' Monthly, September, 1878, 278. 

 FIG. 423. Flower of Clerodendron Thompsoniae, first day; 424, second day. 



