CUAP. IV. 



LYTHEUII SALICABIA. 



159 



by their own» stamens yielded only two poor (or per- 

 haps three) capsules. 



If we take all six legitimate unions together, and 

 all twelve illegitimate unions together, we get the fol- 

 lowing results : — 



Table 26. 



Therefore the fertility of the legitimate unions to that 

 of the illegitimate, as judged by the proportion of the 

 fertilised flowers which yielded capsules, is as 100 to 

 33 ; and judged by the average number of seeds per 

 capsule, as 100 to 46. 



From this summary and the several foregoing tables 

 we see that it is only pollen from the longest stamens 

 which can fully fertilise the longest pistil ; only that 

 from the mid-length stamens, the mid- length pistil; 

 and only that from the shortest stamens, the shortest 

 pistil. And now we can comprehend the meaning of 

 the almost exact correspondence in length between 

 the pistil in each form and a set of six stamens 

 in two of the other forms ; for the stigma of each 

 form is thus rubbed against that part of the insect's 

 body which becomes charged with the proper pollen. 

 It is also evident that the stigma of each form, 

 fertilised in three different ways with pollen from 

 the longest, mid-length, and shortest stamens, is acted 

 on very differently, and conversely that the pollen from 



