268 THE STRUCTURE OF FLOWERS. 



In Corylus, Alnus, and Plantago media, they are polygonal, 

 while Beech has them deeply three-grooved, etc. 



Mr. Edgeworth, in fact, states that the different kinds of 

 pollen of anemophilous plants " are by no means all globular, 

 as Mr. Bennett asserts." 



He notices, however, that " the grasses and Cyperacece, 

 and perhaps the Plantagineoe are without the sticky nature 

 of the outer coat, which obtains through all otiier pollen 

 grains." 



With regard to the versatile condition of the anthers in 

 grasses, and their consequent facility of oscillating on a point, 

 this feature seems to be only the result of the extremely 

 slender filament due to degradation ; * and not quite the 

 same thing as the antero-posterior oscillation which the 

 action of bees has set up in the connectives of Salvia, species 

 of Calceolaria, and Curcuma Zerumbet.f Remembering how 

 the rigidity of the filaments of intercrossing flowers is corre- 

 lated to the retention of some well-defined positions for the 

 anthers, so that insects can be struck by them accurately, 

 and be again struck on the same spot by the stigmas of other 

 flowers, we see that when the stimulus due to intercrossincr 

 has been long withheld, the filaments have become slender, 

 easily waved about by the wind, and versatility of the 



* Plantago media, which is visited, has motionless anthers ; but in 

 the anemophilous species of Plantain they are versatile. 



+ Mr. H. O. Forbes has described and figured a very analogous case 

 in this species of Curcuma of Sumatra. The two anthers project for- 

 wards in contact, they are provided with terminal processes like horns. 

 The style passes between them. When a bee enters the flower it 

 depresses these horns with its head, and so forces the anthers down- 

 wards on to its thorax. The anthers bring the style and stigma down 

 also. In a similar way do some species of Salvia cause the style to be 

 brought down from the hood (4 Naturalist's Wanderings in the Eastern 

 Archipelago, p. 247) . 



