244 



THE LIFE OF THE PLANT 



a tube, called the spur (fig. 70 sp.). 1 The pistil and 

 stamens of this flower are equally singular in shape : 

 the pistil consists of a long twisted ovary (ov.), on the top 

 of which, without any style whatever, the stigma rests, 

 in the shape of a sticky spot at the very entrance into 

 the tube of the spur (stg.). The stamen has no filament, 

 but consists of an anther only (anth.) , situated close to the 



stigma. But all 



.jf&j this does not ex- 



/ haust the pecu- 



^ v liarities of this 



plant. Its pollen 

 is not crumbling 

 dust, but is 

 gathered in each 

 of the two lobes 

 of the anther into 

 a lump, on a stalk 

 which ends at the 

 bottom in a sticky 

 knob on the out- 

 side of the anther (fig. 70, 2). Evidently since the 

 pollen is not set free by itself it cannot reach without 

 external assistance even the stigma of the same 

 flower, although it lies so close to it. This very 

 assistance is given by the insect. In settling upon the 

 lip (iZ), it thrusts its proboscis into the tube of the spur, 

 at the bottom of which a sugary fluid is generally 

 secreted, distinctly seen in Platanthera. The insect 

 invariably comes up against the viscous knob sticking 

 out of the stamen, and in flying off the flower carries 

 away its mass of pollen. This arrangement of the 

 flower is so accurate, and works so perfectly, that even a 

 needle cannot be thrust into the spur in the direction of 



1 Fig. 70 shows the flower of an orchid, all the petals of which are 

 removed except the lip, which is split into two, to show the entrance into 

 the spur and the position of the stigma. 



FIG. 70. 



