Fertilization of the common Blue Lobelia. 261 



opens ; after a time, it protrudes. It has two lobes, but they 

 are folded or pressed together when the flower first opens, 

 and then only expose their perfectly smooth outer or lower 

 sides. When the stigma protrudes from the anther-tube, the 

 lobes open, the smooth outer surface is turned back, the ring 

 of bristles is reflexed on the style, and the upper or inner stig- 

 matic surface of the lobes, covered with short hairs or papillae, 

 makes its appearance below the mouth of the anther-tube, 

 where it faces outwards and downwards, so as to meet any- 

 thing which is thrust into the tube of the corolla. 



When the flower first opens, the length of the style, as 

 compared with that of the stamens, is such that the closed 

 stigma with its ring of spreading bristles is at the bottom of 

 the anther-tube. The style grows rapidly, sweeping the pollen 

 with its ring of bristles, and pressing it towards the mouth of 

 the anther-tube. Towards the end of this stage of growth, 

 the style becomes so long relatively to the stamens, that it 

 presses towards or against the mouth of the anther-tube like a 

 spring. If at this stage a bit of the top of the anther-cases is 

 cut off, the compressed pollen is forced outwards with quite a 

 spirt. 



It is clear that the principal function of all this apparatus is 

 not to fertilize the stigma with the pollen of its own flower. 

 The back of the stigma, which is smooth and has no papillae, 

 alone comes in contact with that pollen, and the stigmatic 

 surface is only displayed when the pollen of its own flower is 

 nearly all expelled from the anthers, and when the stigma is 

 beyond the place at which it would be found. 



But all becomes clear if the function is to enable insects to 

 carry pollen from one flower to another. 



If — a short time after the flower has opened, when the 

 anther-cells have burst, when the anther-tube has opened 

 slightly at the top, when the mouth of the anther-tube is 

 turned downwards, and when the style is growing and is 

 pushing the stigma and its brush towards the mouth of the 

 anther-tube — any pointed object is thrust into the tube, it 

 touches and rubs and pushes a little backwards the stiff bris- 

 tles attached to the connective of the lower anthers. This 

 motion, combined with the thrust of the style and of its brush, 

 forces the pollen through the small opening of the anther- 

 tube downwards in a gentle stream or shower on the back or 

 upper side of the object inserted. A pencil will become co- 

 vered for some length by it. The aperture or slit in the tube 

 of the corolla affords free play to the anther-tube under this 

 treatment. 



Bees frequent this lobelia, and get well dusted on the back 



