M. on successive nights, and they
were found at this latter hour to have risen by an average angle of 9o
above their mid-day position: on the following morning they fell to their
former position. Now it may be observed in the diagram that the leaf rose
during the second night, so that it stood at 6.40 A.M. higher than at 10.20
P.M. on the preceding night; and this may be attributed to the leaf
adjusting itself to the dim light, coming exclusively from above.
Fig. 95. Crambe maritima: circumnutation of leaf, disturbed by being
insufficiently illuminated from above, traced from 7.50 A.M. June 23rd to 8
A.M. 25th. Apex of leaf 15 1/4 inches from the vertical glass, so that the
tracing was much magnified, but is here reduced to one-fourth of original
scale.
(4.) Brassica oleracea (Cruciferae).--Hofmeister and Batalin* state that
the leaves of the cabbage rise at night, and fall by day. We covered a
young plant, bearing 8 leaves, under a large bell-glass, placing it in the
same position with respect to the
* 'Flora,' 1873, p. 437.
[page 230]
light in which it had long remained, and a filament was fixed at the
distance of .
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