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 young leaves of Cannabis sativa sink at night between 30o and 40o beneath the horizon; and Kraus attributes this to epinasty in conjunction with the absorption of water.

From The Power of Movement in Plants by Darwin, Charles

De Vries has shown* that the more or less horizontal position of leaves is in most cases influenced by epinasty, by their own weight, and by apogeotropism.

From The Power of Movement in Plants by Darwin, Charles

At the same time the loop became open and was thus reconverted into a hook, and this apparently was effected by the geotropic movement of the apex in opposition to epinasty.

From The Power of Movement in Plants by Darwin, Charles

This movement is due to epinasty, as is likewise the case with the flowers of T. repens.

From The Power of Movement in Plants by Darwin, Charles

As this latter movement occurred in complete darkness, and with peduncles arising from upright and from dependent branches, it cannot be due to apheliotropism or to epinasty, but must be attributed to geotropism.

From The Power of Movement in Plants by Darwin, Charles