The tracing (Fig. 45)
shows how large, complex, and rapid were the circum-
Fig. 45. Cycas pectinata: circumnutation of young leaf whilst emerging from
the ground, feebly illuminated from above, traced on vertical glass, from 5
P.M. May 28th to 11 A.M. 31st. Movement magnified 7 times, here reduced to
two-thirds of original scale.
nutating movements. The extreme distance from side to side which it passed
over amounted to between .6 and .7 of an inch.
Canna Warscewiczii (Cannaceae).--A seedling with the plumule projecting one
inch above the ground was observed, but not under fair conditions, as it
was brought out of the hot-house and kept in a room not sufficiently warm.
Nevertheless the tracing (Fig. 46) shows that it made two or three
incomplete irregular circles or ellipses in the course of 48 hours. The
plumule is straight; and this was the first instance observed
[page 59]
by us of the part that first breaks through the ground not being arched.
Fig. 46. Canna Warscewiczii: circumnutation of plumule with filament
affixed obliquely to outer sheath-like leaf, traced in darkness on
horizontal glass from 8.
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