T 
118 MR. J. SCOTT ON THE FUNCTIONS AND STRUCTURE OF THE 
Even under these conditions, however, an imperfect fertility is 
induced; as by the dehiscence of the anthers, which closely sur- 
round the stigmas, the pollen-grains are brought into immediate 
contact with the exterior or cireumference of the stigma, into 
whieh they protrude their tubes, and thus induce a variable 
though usually a low grade of fertility. This will be seen by an 
examination of the table beneath, which gives the results from 
four plants of the P. Scotica under the following treatment :— 
Two of the plants were placed under a shaded bell-glass, and had 
their flowers artificially fertilized ; a third was placed under 
similar conditions, so as to guard against the aid of all external 
agencies in the fertilization of the flowers—each of the latter in 
this ease being left to its own innate means ; in the fourth, and 
last, the plant was freely exposed, so as to favour, as far as 
possible, the action of insects or other agents employed in the 
fertilization of the flowers. 
In Table XIIL the results of the protected and artificially ferti- 
lized plants are given in distinct lines, as one of them was very 
weak and produced two poor umbels, the produets of which, 
united with the other, would give a very unfair idea of the nor- 
mal average of seeds produced by these plants under the above 
treatment. If we compare the results, then, of the artificially 
fertilized flowers in the second line alone with those in the first 
line, earefully protected from all external fertilizing agencies, we 
see that the latter, though equally as productive of capsules as the 
former, nevertheless falls far below it in the average of seeds per 
capsule, the proportion in favour of the former being as 2:24 to 1. 
Again, if we compare the results of the protected and unartificially 
fertilized flowers with those from the unprotected flowers, given 
in the fourth line, we see that the latter also exceeds the former in 
the average of seeds per capsule, in the proportion of 1:87 to 1. 
Lastly, by comparing the results of the artificially fertilized 
flowers, in the first line of the table, with those of the unpro- 
tected flowers, in the fourth line, we see that the average fertility 
of the former relatively to the latter is as 1:11 to 1. 
We thus see that the Primula Scotica is capable of self-ferti- 
lization ; but, from its extremely imperfect nature, we are rather 
inclined to regard it as a mere provision against absolute sterility, 
than to suppose that the plant is habitually dependent on such 
manifestly imperfect means for its fertilization ; that, in fact, in 
this species, as in the truly dimorphie, fertilization is largely 
aided by insect or other mechanical agencies; so that, as one of 
