epinasty

American  

[ep-uh-nas-tee] / ˈɛp əˌnæs ti /

noun

Botany.

1. (especially of leaves) increased growth on the upper surface of an organ or part, causing it to bend downward.

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epinasty British  

/ ˈɛpɪˌnæstɪ /

noun

1. increased growth of the upper surface of a plant part, such as a leaf, resulting in a downward bending of the part Compare hyponasty

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Other Word Forms

• epinastic adjective

Etymology

Origin of epinasty

1875–80; epi- + Greek nast ( ós ) pressed close + -y ³

Example Sentences

The term epinasty is used by De Vries* to express greater longitudinal growth along the upper than * 'Arbeiten des Bot.

From Project Gutenberg

The movements thus induced result from a modified form of circumnutation; for, as we shall immediately see, an organ under the influence of epinasty does not generally move in a straight line downwards, or under that of hyponasty upwards, but oscillates up and down with some lateral movement: it moves, however, in a preponderant manner in one direction.

From Project Gutenberg

This shows that there is some growth on all sides of the part, but more on the upper side in the case of epinasty, and more on the lower side in that of hyponasty, than on the other sides.

From Project Gutenberg

At the same time there may be in addition, as De Vries insists, increased growth on one side due to geotropism, and on another side due to heliotropism; and thus the effects of epinasty or of hyponasty may be either increased or lessened.

From Project Gutenberg

He who likes, may speak of ordinary circumnutation as being combined with epinasty, hyponasty, the effects of gravitation, light, etc.; but it seems to us, from reasons hereafter to be given, to be more correct to say that circumnutation is modified by these several agencies.

From Project Gutenberg