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This fact is
shown in two parts of the diagram (Fig. 150) of the movements of Desmodium
gyrans. Strephium floribundum, observed under a high temperature,
[page 406]
made several little triangles at the rate of 43 m. for each. Mimosa pudica,
similarly observed, described three little ellipses in 67 m.; and the apex
of a leaflet crossed 1/500 of an inch in a second, or 0.12 inch in a
minute. The leaflets of Averrhoa made a countless number of little
oscillations when the temperature was high and the sun shining. The zigzag
movement may in all cases be considered as an attempt to form small loops,
which are drawn out by a prevailing movement in some one direction. The
rapid gyrations of the little lateral leaflets of Desmodium belong to the
same class of movements, somewhat exaggerated in rapidity and amplitude.
The jerking movements, with a small advance and still smaller retreat,
apparently not exactly in the same line, of the hypocotyl of the cabbage
and of the leaves of Dionaea, as seen under the microscope, all probably
come under this same head.


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