M. they were in close contact,
so that each had risen 26 1/2o. At noon, on the 29th, they included an
angle of 118o, and at 10 P.M. an angle of 54o, so each had risen 32o. On the
following day they were still more open, and the nocturnal rise was
greater, but the angles were not measured. Two other seedlings were
observed, and behaved during three days in a closely similar manner. The
cotyledons, therefore,
[page 43]
open more and more on each succeeding day, and rise each night about 30o;
consequently during the first two nights of their life they stand
vertically and come into contact.
Fig. 30. Lagenaria vulgaris: circumnutation of a cotyledon, 1 ? inch in
length, apex only 4 3/4 inches from the vertical glass, on which its
movements were traced from 7.35 A.M. July 11th to 9.5 A.M. on the 14th.
Figure here given reduced to one-third of original scale.
In order to ascertain more accurately the nature of these movements, the
hypocotyl of a seedling, with its cotyledons well expanded, was secured to
a little stick, and a filament with triangles of paper was affixed to one
of the cotyledons.
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