ON THE STRUCTURE AND MOVEMENTS OF SOME OTHER SPECIES OF DROSERA.
Drosera anglica Drosera intermedia Drosera capensis Drosera
spathulata Drosera filiformis Drosera binata Concluding remarks.
I examined six other species of Drosera, some of them inhabitants of
distant countries, chiefly for the sake of ascertaining whether they
caught insects. This seemed the more necessary as the leaves of some of
the species differ to an extraordinary degree in shape from the rounded
ones of Drosera rotundifolia. In functional powers, however, they
differ very little.
[Drosera anglica (Hudson).* The leaves of this species, which was sent
to me from Ireland, are much elongated, and gradually widen from the
footstalk to the bluntly pointed apex. They stand almost erect, and
their blades sometimes exceed 1 inch in length, whilst their breadth is
only the 1/5 of an inch. The glands of all the tentacles have the same
structure, so that the extreme marginal ones do not differ from the
others, as in the case of Drosera rotundifolia. When they are irritated
by being roughly touched, or by the pressure of minute inorganic
particles, or by contact with animal matter, or by the absorption of
carbonate of ammonia, the tentacles become inflected; the basal portion
being the chief seat of movement. Cutting or pricking the blade of the
leaf did not excite any movement. They frequently capture insects, and
the glands of the inflected tentacles pour forth much acid secretion.
Bits of roast meat were placed on some glands, and the tentacles began
to move in 1 m. or
* Mrs. Treat has given an excellent account in The American
Naturalist, December 1873, p. 705, of Drosera longifolia (which is a
synonym in part of Drosera anglica), of Drosera rotundifolia and
filiformis. [page 279]
1 m. 30 s.; and in 1 hr. 10 m. reached the centre. Two bits of boiled
cork, one of boiled thread, and two of coal-cinders taken from the
fire, were placed, by the aid of an instrument which had been immersed
in boiling water, on five glands; these superfluous precautions having
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