SECT. XIII. 



ORCHIS PYEAMIDALIS. 



395 



adheres to the proboscis, and is withdrawn with it into 

 the air, carrying the two pollinia (fig. 80) on its exterior 

 surface. Almost instantly the saddle is exposed to the 

 air, a rapid movement takes place. The two flaps curl 



Fig. 79. Disc of Or- 

 chis pyramidalis 

 seen from above, 

 with one pollinium, 

 flattened by force. 



Pig. 80. Pollinia of 

 Orchis pyramidalis, 

 attached to saddle- 

 shaped disc. 



Fig. 81. Pollinia of Orchis pyrami- 

 dalis with the disc contracted. 



inwards (fig. 81), and embrace the proboscis, and the 

 pollinia, at first parallel, become divergent. A second 

 movement now takes place, which causes the divergent 

 pollinia (fig. 81), which are at right angles to the pro- 

 boscis, to sweep through ninety 

 degrees towards the tip of the pro- 

 boscis, so as to become depressed, 

 and lie on each side of it. Hence, 

 when a moth pushes its proboscis 

 between the guiding ridges of the 

 labellum into the nectary of an- 

 other flower, the two thick ends 

 of the pollinia will exactly strike 

 against the two stigmas. These 

 stigmas are so viscid that they hold 

 and rupture the elastic threads Fig. 82. Poiiinia of orchis py - 



i -i i -i ji i j> -n ramidalis : a, as withdrawn 



Which bind the packets OI pollen by the insertion of a needle ;b, 



as after the second contraction. 



grains together, and some dark 

 green grains are seen even with the naked eye remain- 

 ing on the two white stigmatic surfaces. In the Orchids, 

 as in all other flowering plants, tubes sent out by the 



