But the tracings made under such unnatural
conditions are not worth giving; and it need only be said that the lines
were decidedly zigzag, and that small loops were occasionally formed. We
may therefore conclude that the epicotyl circumnutates whilst still arched
and before it has grown tall enough to break through the surface of the
ground.
In order to observe the movements of the epicotyl at a somewhat more
advanced age, a filament was fixed near the base of one which was no longer
arched, for its upper half now formed a right angle with the lower half.
This bean had germinated on bare damp sand, and the epicotyl began to
straighten itself much sooner than would have occurred if it had been
properly planted. The course pursued during 50 h. (from 9 A.M. Dec. 26th,
to 11 A.M. 28th) is here shown (Fig. 22); and we see
Fig. 22. Vicia faba: circumnutation of young epicotyl, traced in darkness
during 50 hours on a horizontal glass. Movement of bead of filament
magnified 20 times, here reduced to one-half of original scale.
that the epicotyl circumnutated during the whole time.
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