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. Its basal part grew
so much during the 50 h. that the filament at the end of our observations
was attached at the height of .4 inch above the upper surface of the bean,
instead of close to it. If the bean had been properly planted, this part of
the epicotyl would still have been beneath the soil.

Late in the evening of the 28th, some hours after the above observations
were completed, the epicotyl had grown much straighter, for the upper part
now formed a widely open angle with the lower part. A filament was fixed to
the upright basal part, higher up than before, close beneath the lowest
scale-like process or homologue of a leaf; and its movement was traced
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during 38 h. (Fig. 23). We here again have plain evidence of continued
circumnutation. Had the bean been properly planted, the part of the
epicotyl to which the filament was attached, the

Fig. 23. Vicia faba: circumnutation of the same epicotyl as in Fig. 22, a
little more advanced in age, traced under similar conditions as before,
from 8.40 A.M. Dec. 28th, to 10.50 A.M. 30th. Movement of bead here
magnified 20 times.

movement of which is here shown, would probably have just risen above the
surface of the ground.

Lathyrus nissolia (Leguminosae).--This plant was selected for observation
from being an abnormal form with grass-like leaves.