They continued to move in the same manner for the
following two months, by which time they had increased greatly in size,
their petioles being no less than .8 of an inch in length, and two true
leaves had by this time been developed.
Trifolium strictum.--On the first day after germination the cotyledons,
which are provided with a pulvinus, stood at noon horizontally, and at
night rose to only about 45o above the horizon. Four days afterwards the
seedlings were again observed at night, and now the blades stood vertically
and were in contact, excepting the tips, which were much deflexed, so that
they faced the zenith. At this age the petioles are curved
[page 310]
upwards, and at night, when the bases of the blades are in contact, the two
petioles together form a vertical ring surrounding the plumule. The
cotyledons continued to act in nearly the same manner for 8 or 10 days from
the period of germination; but the petioles had by this time become
straight and had increased much in length. After from 12 to 14 days the
first simple true leaf was formed, and during the ensuing fortnight a
remarkable movement was repeatedly observed.
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