REPRODUCTIVE ORGANS IN THE PRIMULACEE. 87 
certainly erroneous, I will give, for the satisfaction of those who 
have had no means of testing the point at issue, the results of my 
own experience. The following are the results from plants grow- 
ing together in a bed and freely exposed to the visits of insects*. 
Seo ee UR 
Zo - EN LEE E617 H 
Bg 2282982, Es|E. 
ES BÍHEEZETESL 88 | 88 
28 SBROBROPRS SE | 28 
AP nS Bi SBI BS) A ZA S 
Short-styled Aurieulas......| 10 | 33 | 287 | 2734 | 50 | 4142 
Long-styled Auriculas ...... 10 | 41 323 | 1816 | 50 | 2215 
Again, in the following table the results are given from plants 
carefully protected from insects ; though in no way. effecting their 
fertility, as I proved by artificial fertilization. 
| 
Nunber of ae of | SC of of 
dares: umbels owers seeds 
I produced. | produced. | produced. 
Short-styled Auriculas ...... 6 26 | 23 104 
Long-styled Auriculas ...... 6 22 | 8 
If we compare the seed-results im the former of the above 
tables, we see that the short-styled are the more fertile—exceed- 
ing the long-styled in about the proportion oftwo to one. Again, 
in the latter table we see that the short-styled forms are also the 
more productive, though, comparatively with the results from the 
exposed plants, extremely sterile, showing us clearly how much 
these plants are dependent for their fertilization on insects or 
other mechanical agencies. "This is more especially the case in 
the long-styled plants whose stigma stands high above the stamens, 
so that pollen cannot possibly reach the stigma without mechanical 
aid. The seed-results of this form in my table were the product 
of a single umbel infested with aphides; and which I have no 
doubt were the fertilizing agents, as not a single seed was pro- 
duced upon any of the others. In the case of the short-styled 
plants, on the other hand, a low degree of fertility may be pretty 
regularly effected: the stamens surrounding the mouth of the 
corolla-tube are more or less inclined inwards, so that the anthers 
* This and the succeeding Tables are arranged after the manner of Mr. Dar- 
win (loc. cié.). It will be observed, however, that instead of giving the weight of 
the seeds, as he has done, Ihave given their number. This alteration has been 
made at the suggestion of Mr. Darwin, who considers that greater exa ctitude is 
thereby attained. 
