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"The Power of Movement in Plants"

The cotyledons of
the other seedling were 1.3 inch in length, and a minute true leaf had been
formed; they had fallen at 10 P.M. to 70o beneath the horizon. On June
25th, the true leaf of this latter seedling was .9 inch in length, and the
cotyledons occupied nearly the same position at night. By July 9th the
cotyledons appeared very old and showed signs of withering; but they stood
at noon almost horizontally, and at 10 P.M. hung down vertically.
Gossypium herbaceum.--It is remarkable that the cotyledons of this species
behave differently from those of the last. They were observed during 6
weeks from their first development until they had grown to a very large
size (still appearing fresh and green), viz. 2 ? inches in breadth. At this
age a true leaf had been formed, which with its petiole was 2 inches long.
During the whole of these 6 weeks the cotyledons did not sink at night; yet
when old their weight was considerable and they were borne by much
elongated petioles. Seedlings raised from some seed sent us from Naples,
behaved in the same manner; as did those of a kind cultivated in Alabama
and of the Sea-island cotton.


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