<^rethusa and Togonia 



in retiring slides his back against the receptive 

 viscid stigma, which retains a portion of the pollen, 

 and thus effects the cross-fertilization (C). Pro- 

 fessor Gray surmised that the pollen was withdrawn 

 on the insect's head, and it might be so withdrawn, 

 but in other allied orchids 

 of the tribe Arethusa, how- 

 ever, in which the struc- 

 ture is very similar, the 

 pollen is deposited on the 

 thorax, and such is prob- 

 ably the fact in this species. 

 In either case, cross-fertil- 

 ization would be effected. 

 Nothing else is possible, 

 and whether it is Bombus or not that effects it, the 

 method is sufficiently evident. 



The sweet-pogonia, or grass-pink of our sedgy 

 swamps {Pogonia opJiioglossoidcs), a solitary rosy 

 blossom, nodding on its slender stem above the 

 grasses, is no less welcome an episode to the saun- 

 tering botanist than its cousin Arethusa. Its per- 

 fume, suggesting ripe red raspberries, is unique in 

 the wild bouquet. 



The bee as well as the botanist recognizes 

 these flowers as closely akin, and visits the pogonia 



155 



