Afterwards the sleeping
movement is well displayed, though to a variable degree, and is long
continued. We shall hereafter meet with a nearly parallel case with the
leaves of Sida rhombifolia. The cotyledons of L. Gebelii are only slightly
raised at night, and differ much in this respect from the three species in
our list.
[page 309]
Trifolium.--The germination of 21 species was observed. In most of them the
cotyledons rise hardly at all, or only slightly, at night; but those of T.
glomeratum, striatum and incarnactum rose from 45o to 55o above the
horizon. With T. subterraneum, leucanthemum and strictum, they stood up
vertically; and with T. strictum the rising movement is accompanied, as we
shall see, by another movement, which makes us believe that the rising is
truly nyctitropic. We did not carefully examine the cotyledons of all the
species for a pulvinus, but this organ was distinctly present in those of
T. subterraneum and strictum; whilst there was no trace of a pulvinus in
some species, for instance, in T. resupinatum, the cotyledons of which do
not rise at night.
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