Page:Insectivorous Plants, Darwin, 1899.djvu/23

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Chap. I.] STRUCTURE OF THE LEAVES. 3

ing vertically upwards. The shape and general appearance of a leaf is shown, as seen from above, in Fig. 1, and as seen laterally, in Fig. 2. The leaves are commonly a little broader than long, but this was not the case in the one here figured. The whole upper surface is covered with gland-bearing

Fig. 1[1].

(Drosera rotundifolia.)

Leaf viewed from above ; enlarged four times.

filaments, or tentacles, as I shall call them, from their manner of acting. The glands were counted on thirty-one leaves, but many of these were of unusually large size, and the average number was 192; the greatest number being 260, and the least 130. The glands are each surrounded by large drops of extremely viscid secretion, which, glittering in the sun,

have given rise to the plant's poetical name of the sun-dew.

  1. The drawings of Drosera and Dionaea, given in this work, were made for me by my son, George Darwin; those of Aldrovanda, and of the several species of Utricularia, by my son Francis. They have been excellently reproduced on wood by Mr. Cooper, 188 Strand.