186 VANDE.E. CiiAP. VII. 



balls of pollen, and tearing the loosely attached spike- 

 like anther from the top of the column. The polliniuni 

 is always ejected with its viscid disc foremost. I 

 imitated the action with a minute strip of whalebone, 

 slightly weighted at one end to represent the disc ; 

 this was then bent half round a cylindrical object, 

 the upper end being at the same time gently held by 

 the smooth head of a pin, to represent the retarding 

 action of the anther, the lower end was then suddenly 

 set free, and the whalebone was pitched forward, like 

 the polliniuni of the Catasetum, with the weighted 

 end foremost. 



That the disc is first jerked out of the stigmatic 

 chamber, I ascertained by pressing the middle of the 

 pedicel ; and when I touched the antenna the disc 

 instantly sprung forth, but, owing to the pressure on 

 the pedicel, the pollinium was not dragged out of the 

 anther-cell. Besides the spring from the straighten- 

 ing of the pedicel, elasticity in a transverse direction 

 comes into play : if a quill be split lengthways, and 

 the half be forced longitudinally on a too thick pencil, 

 immediately the pressure is removed the quill jumps 

 off; and an analogous action takes place with the 

 pedicel of the pollinium, owing to the sudden inward 

 curling of its edges, when set free. These combined 

 forces suffice to eject the pollinium with considerable 

 force to the distance of two or three feet. Several 

 persons have told me that, when touching the flowers 

 of this genus in their hothouses, the pollinia have 

 struck their faces. I touched the antenna; of C. caV- 

 losum whilst holding the flower at about a yard's 

 distance from a window, and the pollinium hit the 

 pane of glass, and stuck by its adhesive disc, to the 

 smooth vertical surface. 



The following observations on the nature of the 



