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INSECTIVOROUS PLANTS.

CHAPTER I.

DROSERA ROTUNDIFOLIA, OR THE COMMON SUN-DEW.

Number of insects captured-Description of the leaves and their appendages or tentacles-Preliminary sketch of the action of the various parts, and of the manner in which insects are captured Duration of the inflection of the tentacles-Nature of the secretion-Manner in which insects are carried to the centre of the leaf-Evidence that the glands have the power of absorptionSmall size of the roots.

DURING the summer of 1860, I was surprised by finding how large a number of insects were caught by the leaves of the common sun-dew (Drosera rotundifolia) on a heath in Sussex. I had heard that insects were thus caught, but knew nothing further on the subject.* I

As Dr. Nitschke has given ('Bot. Zeitung,' 1860, p. 229) the bibliography of Drosera, I need not here go into details. Most of the notices published before 1860 are brief and unimportant. The oldest paper seems to have been one of the most valuable, namely, by Dr. Roth, in 1782. There is also an interesting though short account of the habits of Drosera by Dr. Milde, in the 'Bot. Zeitung,' 1852, p. 540. In 1855, in the 'Annales des Sc. nat. bot.' tom. iii. pp. 297 and 304, MM. Groenland and Trécul each published papers, with figures, on the structure of the

leaves; but M. Trécul went so far as to doubt whether they possessed any power of movement. Dr. Nitschke's papers in the 'Bot. Zeitung' for 1860 and 1861 are by far the most important ones which have been published, both on the habits and structure of this plant; and I shall frequently have occasion to quote from them. His discussions on several points, for instance on the transmission of an excitement from one part of the leaf to another, are excellent. On Dec. 11, 1862, Mr. J. Scott read a paper before the Botanical Society of Edinburgh,

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