CHAP. IV. LYTHRUM SALICARIA. 143 



both sets of stamens in all three forms, is copied from 

 H. Miiller; they are arranged in the order of their 



size : 



Pollen-grains from longest stamens of short-styled form 9J to 10J 



mid-styled 



mid-length stamens of long-styled 

 short-styled 



shortest stamens of long-styled 

 " " mid-styled 



We here see that the largest pollen-grains come from 

 the longest stamens and the least from the shortest; 

 the extreme difference in diameter between them being 

 as 100 to 60. 



The average number of seeds in the three forms was 

 ascertained by counting them in eight fine selected 

 capsules taken from plants growing wild, and the 

 result was, as we have seen, for the long-styled (neg- 

 lecting decimals) 93, mid-styled 130, and short-styled 

 83. I should not have trusted in these ratios had I 

 not possessed a number of plants in my garden which, 

 owing to their youth, did not yield the full comple- 

 ment of seed, but were of the same age and grew 

 under the same conditions, and were freely visited by 

 bees. I took six fine capsules from each, and found 

 the average to be for the long-styled 80, for the mid- 

 styled 97, and for the short-styled 61. Lastly, legiti- 

 mate unions effected by me between the three forms 

 gave, as may be seen in the following tables, for the 

 long-styled an average of 90 seeds, for the mid-styled 

 117, and for the short-styled 71. So that we have 

 good concurrent evidence of a difference in the average 

 production of seed by the three forms. To show that 

 the unions effected by me often produced their full 

 effect and may be trusted, I may state that one mid- 

 styled capsule yielded 151 good seeds, which is the 



