OF FLOWERING PLANTS. ; 69 
vouched for, might well cause a rising doubt. He tells 
us that the pollen of one species of Passion Flower will 
fertilize the ovules of another species, though the ovules 
of the first may not in turn be fertilized by the pollen of ` 
the second. Thus Tacsonia mollissima will fertilize the 
ovules of Passiflora racemosa, but Passiflora will not fer- 
tilize Tacsonia. 
Interesting as may be the means resorted to in the ca- 
ses above mentioned, to secure cross-fertilization (mostly 
through the medium of insects) they yield in fascination 
to the adaptations by which the same results are accom- 
plished by the same agents in many Orchids. 
We must refer those who wish to go into the details 
of fertilization, as it is brought about in this gorgeous 
family, to Mr. Darwin’s interesting volume on “Fertili- 
zation of Orchids by Insects.” They will there find the 
subject treated of by a master mind in such inquiries. 
The temptation to meddle in work so much better done 
elsewhere, is too great, and we should be surprised at 
ourselves if we passed the subject entirely by. Among 
the Orchids and Milkweeds (Asclepias), we find that the 
pollen, in place of being loose, or at the most slightly 
coherent, is here neatly done up in two small decanter- __ 
shaped packets, which are connected at the top of the _ 
necks by a small, viscid BiG aes cs a 
Let us imagine that on some bright summer morning, a 
humble bee, for example, happening to be out in search 
of the material from which to get its store of honey, 
alights on one of ‘these Orchids. Standing, perchance, 
on the large lip (so prominent among these flowers), it 
dips its head down to the bottom of the flower in search 
of nectar. The chances are ten to one that its forehead 
strikes directly upon this viscid gland connecting the two | 
