111. | THE MECHANISMS OF FLOWERS. 395 
in being drawn out carries with it pollen, which in the next 
flower is left attached to the stigmatic edge of the disk which 
terminates the style. And in the case of Vinca major, which 
Darwin had never seen visited by insects in England nor bearing 
fruit, he obtained good seed by repeatedly passing a fine bristle 
down among the stamens in six flowers on two plants, and thus 
effecting both cross- and self-fertilisation. Another English ob- 
server (122A) was led by Darwin's account to perform the same 
k xperiment on Vinea rosea, L.; he obtained good seed, though he 
had before found the plant always unproductive. A third English 
‘observer (636A) maintained that he had got good seed from 
Vinca rosea when left to itself, But Darwin showed that this last 
Fic, 131.—Vinea minor, L, 
Flower, after removal of the anterior part of the corolla. 
_ @, ovary; bb, two yellow honey-glands at the base of the ovary; ¢, style; d, point where the 
aments separate from the corolla, marked externally by depressions; d,-e, filament with its 
ward bend ; e, f, anther, dehiscing introrsely ; g, thickening of the style; h, disk-shaped end of 
veg surrounded with viscid matter and functioning as a stigma on two sides of its lower 
e; k, hairs upon the stigma-disk which receive the pollen as it issues from the anthers. 
‘result was faulty, as the plant stood in a greenhouse with open 
windows, by which moths might enter (153, p. 831). 
_ JDelpino, unaware of these observations, gave later a full 
wccount, agreeing with Darwin’s, of the mechanism of the flower 
of Vinca; his description was taken from V. rosea, in which the 
lower border of the stigmatic disk extends downwards in the form 
. inverted cup (173, pp. 15-17). Hildebrand afterwards gave 
his res of the flowers, which illustrated Delpino’s account (352). 
~ None of the foregoing observers seem to have seen any insects 
except Thrips on any species of Vinca, which is remarkable, as 
V. minor in its season (beginning of April until May) is most 
conspicuous and rich in honey, and in my experience is in sunny 
weather visited abundantly by insects. The tube of the corolla is 
11 mm. long in V. minor, but insects can easily insert their heads 
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