104 



pollen grains are united by fine threads, then into larger, 

 finally forming pellets, and having a stalk attacked to a cen- 

 tral stalk. At the lower end of this stalk is attached a but- 

 ton-shaped disc, the face of which is exposed and is on a line 

 with the surface of the anther, so that these two discs look 

 toward each other across the broad, intervening stigmatic 

 space. When a finder or any small body touches these discs 

 they adhere so firmly that the attached pollinia or pollen 

 masses are dragged out of the cell and carried away entire. 

 When a hawk-moth like Sphynx drupifearum visits these 

 flowers and presses its head into the center of the flower to 

 get the nectar out of the nectary a pollen mass will be fixed 

 to each eye, and on withdrawal these will stand as shown in 

 figure. 



But they are soon turned downward as shown to the right. 

 This is due not to their own weight but to a contraction in 

 the drying of one side of the tleshy piece which connects the 

 disc with the stalk. When the moth passes from one flower 

 to that of another plant, and thrusts its proboscis down to 

 get the nectar the pollen rnasses on the insect will be brought 

 in contact with the large viscid stigma; either some of the 

 pellets will be left on the stigma or a whole pollen mass." 



Cata setum. This is interesting as regards its pollina- 

 tion. It is hot uncommon now in greenhouses. Its remark- 

 able adoption whs flrst pointed out by Darwin. In this 

 orchid the pollina and stigmas are in diflerent flowers. Like 

 Habenaria the pollinun is furnished with a viscid disc, but 

 in this case the insect does not touch the viscid diec. The 

 flower is sensitive and throws the pollinium at the insect. Sir 

 John Lubbock says that Darwin irritated one of the flowers 

 in his presence and the pollinium was thrown nearly three 

 feet In a staminate flower the pollinum, which is in a state of 



