CiiAr. V. DENDBOBIUM CHETSANTHUM. 141 



represented sideways in fig. B, and frontways in fig. 

 C. By this springing action the anther scoops the 

 poUinium out of the concave clinandrum, and pitches 

 it up in the air, with exactly the right force so as to 

 fall down on the middle of the viscid stigma, where it 

 adheres. 



Under nature, however, the action cannot be as thus 

 described, for the labellum hangs downwards ; and to 

 understand what follows, the drawing should be placed 

 in an almost reversed position. If an insect failed to 

 remove the poUinium by means of the viscid matter 

 from the rostellrmi, the poUinium would first be jerked 

 downwards on to the protuberant surface of the label- 

 lum, placed immediately beneath the stigma. But it 

 must be remembered that the labellum is elastic, and 

 that at the same instant that the insect, in the act of 

 leaving the flower, lifts up the lip of the anther, and 

 so causes the pollinium to be shot out, the labellum 

 will rebound back, and striking the poUinium wiU' 

 pitch it upwards, so as to hit the adhesive stigma. 

 Twice I succeeded in effecting this by imitating the 

 retreat of an insect, with the flower held in its natural 

 position ; and on opening it, found the pollinium 

 glued to the stigma. 



This view of the use of the elastic filament, seeing 

 how complicated the action must be, may appear 

 fanciful ; but we have seen so many and such curious 

 adaptations, that I cannot believe the strong elasticity 

 of the filament and the thickening of the middle part 

 of the labeUum to be useless points of structure. If 

 the action be as I have described, we can perceive 

 their meaning, for it would be an advantage to the 

 plant that its single large pollen-mass should not be 

 wasted, supposing that it failed to adhere to an insect 

 by means of the viscid matter from the rostellum. 



