Is the intention here to be thought any the less real because there are
other species of Drosera which are not so perfectly adapted for
fly-catching, owing to the form of their leaves and the partial or total
want of cooperation of their scattered bristles? One such species, D.
filiformis, the thread-leaved sundew, is not uncommon in this country, both
north and south of the district that Dionaea locally inhabits. Its leaves
are long and thread-shaped, beset throughout with glutinous gland-tipped
bristles, but wholly destitute of a blade. Flies, even large ones, and even
moths and butterflies, as Mrs. Treat and Mr. Canby affirm (in the American
Naturalist), get stuck fast to these bristles, whence they seldom escape.
Accidental as such captures are, even these thread-shaped leaves respond
more or less to the contact, somewhat in the manner of their brethren. In
Mr. Canby's recent and simple experiment, made at Mr. Darwin's suggestion,
when a small fly alights upon a leaf a little below its slender apex, or
when a bit of crushed fly is there affixed, within a few hours the tip of
the leaf bends at the point of contact, and curls over or around the body
in question; and Mrs. Treat even found that when living flies were pinned
at half an inch in distance from the leaves, these in forty minutes had
bent their tips perceptibly toward the flies, and in less than two hours
reached them! If this be confirmed--and such a statement needs ample
confirmation--then it may be suspected that these slender leaves not only
incurve after prolonged contact, just as do the leaf-stalks of many
climbers, but also make free and independent circular sweeps, in the manner
of twining stems and of many tendrils.
Correlated movements like these indicate purpose. When performed by
climbing plants, the object and the advantage are obvious. That the
apparatus and the actions of Dionaea and Drosera are purposeless and
without advantage to the plants themselves, many have been believed in
former days, when it was likewise conceived that abortive and functionless
organs were specially created "for the sake of symmetry" and to display a
plan; but this is not according to the genius of modern science.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account