The cotyledons were well developed, being .9 of an
inch in length, .22 in breadth, and .15 in thickness. The almost
cylindrical hypocotyl, now bearing a minute spinous bud on its summit, was
only .45 of an inch in height, and .19 in diameter. The tracing (Fig. 31)
shows the combined movement of the hypocotyl and of one of the cotyledons,
from 4.45 P.M. on May 28th to 11 A.M. on the 31st. On the 29th a nearly
perfect ellipse was completed. On the 30th the hypocotyl moved, from some
unknown cause, in the same general direction in a zigzag line; but between
4.30 and 10 P.M. almost completed a second small ellipse. The cotyledons
move only a little up and down: thus at 10.15 P.M. they stood only 10o
higher than at noon. The chief seat of movement therefore, at least when
the cotyledons are rather old as in the present case, lies in the
hypocotyl. The ellipse described on the 29th had its longer axis directed
at nearly right angles to a line joining the two cotyledons. The actual
amount of movement of the bead at the end of the
[page 45]
filament was, as far as could be ascertained, about .
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