68 OPHEE^. Chap. II 



compel motlis to insert their proboscides symmetrically 

 into the nectary, and there would be no advantage in 

 their doing so. 



Gifmnadeiiia alhida. — The structure of the flower of 

 this species resembles in most respects that of the 

 last ; but, owing to the upturning of the labellum, it 

 is rendered almost tubular. The naked elongated 

 discs are minute and approximate. The stigmatic sur- 

 faces are partially lateral and divergent. The nectary 

 is short, and full of nectar. Small as the flowers are, 

 they seem highly attractive to insects : of the eighteen 

 lower flowers on one spike, ten had both, and seven 

 had one pollinium removed ; on some older spikes all 

 the pollinia had been removed, except from two or 

 three of the uppermost flowers. 



Gymnadenia odoratissima is an inhabitant of the 

 Alps, and is said by Dr. H. Miiller* to resemble in 

 all the above characters G. conopsea. As the flowers, 

 which are pale coloured and highly perfumed, are not 

 visited by butterflies, he believes that they are fertilised 

 exclusively by moths. The North American G. tri- 

 dentata, described by Professor Asa Gray,t differs in an 

 important manner from the foregoing species. The 

 anther opens in the bud, and the pollen-grains, which 

 m the British species are tied together by very weak 

 threads, are here much more incoherent, and some in- 

 variably fall on the two stigmas and on the naked 

 cellular tip of the rostellum ; and this latter part, 

 strange to say, is penetrated by the pollen-tubes. The 

 flowers are thus self-fertilised. Nevertheless, as Pro- 

 fessor Gray adds, " all the arrangements for the removal 



♦ 'Nature,* Dec. 31, 1874, p. note p. 200 ; and vol. xxxvi. 18G3, 



109. p. 293. In the latter paper he 



t ' American Journal of Science,' adds some remarks on G.Jlava and 



vol. xxxiv. 1862, p. 426, and foot- nivea. 



