72 THE FERTILIZATION OF FLOWERING PLANTS. 
was a thing not to be thought of. Dr. Hildebrand in- 
forms us however, that though the stigma of Corydalis 
cava be completely dusted over with pollen from the same 
flower, yet no seed will set if insects be excluded from 
carrying pollen from flower to flower. This fact is, as 
will be observed, another illustration of Mr. Darwin’s law 
of prepotency of pollen taken from one flower, and applied 
to another. Professor Gray also calls attention to the 
“effectual activity of so large an insect as the bumble-bee 
in fertilizing our Corydalis a aurea” (Golden Corydalis). 
Just now we can point to but one instance in which a 
plant of high order is found to produce perfect embryos, 
without the ovules having been previously fertilized ac- 
cording to the known method. In the Kew Gardens, 
near London, has been kept for many years a plant of the 
WS family, which furnishes this one example. Dr. 
ker writes to Humboldt concerning it, as follows: 
“Our t Coelebogyne still flowers with my father at Kew, as 
well as in the Garden of the Horticultural Society. It 
ripens its seeds regularly. I have repeatedly examined 
it with care, but have never been able to discover a pene- 
tration of pollen utricles into the stigma, nor any traces 
of their presence in the latter or in the style.” This plant 
belongs to the old Linnzan class Diccia. It is unisexual, 
and as there exists only (so far as known) the fema 
plant in England, it is difficult to conceive how the fertil- 
ization 
i a for the anthers, they do not oeh to have 
We may still b pese before accepting 
i of ps ss 
1es 
s Ci 
