Nyctitropic definitions and example sentences on Wordnik

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Definitions (2)

In botany, characteristic of, affected by, or exhibiting nyctitropism. We come now to the nyctitropic or sleep movements of leaves. It should be remembered that we confine this term to leaves which place their blades at night either in a vertical position or not more than 30° from the vertical,—that is, at least 60° above or beneath the horizon. Darwin, Movement in Plants, vii. 317.

One species of Phyllanthus takes up in sunshine the nyctitropic attitude of another species. — More Letters of Charles Darwin — Volume 2
From their vertical nyctitropic position the leaves of this Phyllanthus might return to horizontality, traversing 90 deg, in two ways, either to their own or to the opposite side of the branch; on the latter way no rotation would be required, while on the former each leaf must rotate on its own axis in order that its upper surface may be turned upwards. — More Letters of Charles Darwin — Volume 2