SOME PLANT MARRIAGES 



437 



ing sensitive projections or antennae is touched (and bees visiting the flower 

 to gnaw at the labellurn inevitably come in contact with it), " the edges of 

 the upper membrane of the disc," says Darwin, " which are continuously 

 united to the surrounding surface, instantaneously rupture, and the disc 

 is set free. The highly elastic 

 pedicel then instantly flirts the 

 heavy disc out of the stigmatic 

 chamber with such force that the 

 whole pollinium is ejected, bring- 

 ing away with it the two balls of 

 pollen, and tearing the loosely 

 attached spike-like anther from 

 the top of the column (fig. 509). 

 The pollinium is always ejected 

 with its viscid disc foremost." 



The force of the discharge will 

 sometimes send the pollinium a dis- 

 tance of two or three feet. One 

 of the attendants at Kew Gardens 

 told the writer that he was once 

 severely rated by a lady who had 

 been struck in the face by the 

 pollinium of Catasetum saccatum, 

 and had come to him with the disc 

 yet sticking to her cheek! Such 

 experiences are not uncommon. 

 Lord Avebury saw a flower of 

 Catasetum, callosum precipitate its 

 pollinium a distance of three feet, 

 when it hit a pane of glass and 

 adhered to it. " From the large 

 size of the flower, more especially 

 of the viscid disc, and from its 

 wonderful power of adhesion," says 

 Darwin, " we may safely infer that 

 the flowers are visited by large 

 insects. The viscid matter sticks 

 so firmly when it sets hard, and 

 the pedicel is so strong (though 

 very thin and only one-twentieth of an inch in breadth at the hinge) 

 that to my surprise it supported for a few seconds a weight of 1,262 

 grains that is, nearly three ounces ; and it supported for a considerable 

 time a slightly less weight." Needless to say, no effort which an insect 

 thus encumbered could exert would remove the disc and pedicel ; " but the 



Photo by] [E. Step. 



FIG. 540. BIRD'S-XEST ORCHIS 



(Neottia nidus-avis). 



An Orchis without leaves and with yellow-brown tlowers. The 

 roots take the form of a mass of thick fibres whose interlac- 

 ing is supposed to look like a bird's nest. 



