616 OCCASIOIfAL XOTES OX PLAXTS, 



form a small vestibule or antechamber to the tube formed by the 

 claws of the two lips. From the horizontal position of this tube 

 the stamens lie, as it were, on the ceiling ; the anthers presenting- 

 the pollen downwards and facing the interior of the tube. At 

 the end of the tube is the spur containing nectar. An insect 

 alighting on the stage, offered by the large lower lip, and going 

 on to the centre of the flower, would find itself just within the 

 vestibule or antechamber of the tube, but would also find its way 

 barred by the palate attached to the lower lip, which crosses the 

 entrance to the tube just inside the antechamber. It must be 

 borne in mind that the tube is not perfect, but is split down its 

 whole length. The insect being already in its mouth, the very 

 slightest attempt to go on, or to force its way in, separates the 

 two parts of the tube, and opens a passage to the nectary. The 

 palate, by being attached to the lower lip, is at the same time 

 carried away from the mouth of the tube by the depression of 

 the lip. So easily do the upper and lower parts of the tube 

 separate, that the mere breathing down upon the broad surface 

 of the lower lip accomj)lishes it. Indeed it is quite possible that 

 the weight of an insect on the lip would depress it, and so open 

 the tube. In either case the insect has a free open way to the 

 nectary ; but to reach it, must of necessity, past so closely under 

 the ojDen side of the anthers (attached as I have said to the 

 ceiling) that it cannot avoid brushing off the pollen. It cannot, 

 either in its passage in or out touch the stigma, because it is 

 shielded by the backs of the broad anthers. The pollen is so 

 adhesive that, if the anther is touched with a needle a consider- 

 able quantity is taken away, so that the insect can scarcely fail ta 

 carry off a large portion. 



But independently of this provision to insure the dissemination 

 of the pollen by means of insects ; there seems to be a special 

 provision made to prevent the stigma receiving any pollen from 

 the anthers of its own flower. Almost immediately upon the 

 maturing of the pollen, the whole corolla falls off, carrying with 



