Bot. [n. of action from prec.: see NUTATION.] A movement characteristic of growing plants, due to increased growth at different points round the axis in succession, whereby the growing part (e.g., the apex of a stem) describes a more or less circular spiral path. (See NUTATION.)
[1875. Bennett & Dyer, trans. Sachs’ Bot., III. iv. 766. Curvatures … caused by the unequal growth of different sides of an organ may be called Nutations…. It is common for the apices of erect stems above the curved growing part to move round in a circle or ellipse, the region of most active growth moving gradually, as it were, round the axis. This kind of nutation may be termed a Revolving Nutation.]
1880. Darwin, Movem. Pl., 1. This movement has been called by Sachs ‘revolving nutation’; but we have found it much more convenient to use the terms circumutation and circumnutate.
1882. Garden, 14 Jan., 32/3. The method of climbing by twiners was a modification of the property of ‘circumnutation.’
So Circumnutatory a., pertaining to circumnutation.
1880. Athenæum, 18 Dec., 817/2. The movements of climbing plants … are modifications of this circumnutatory tendency.
