circumnutate

from The Century Dictionary.

• To nod or turn about; specifically, in botany, to move about in a more or less circular or elliptical path: said of the apex of a stem and of other organs of a plant. See circumnutation.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To pass through the stages of circumnutation.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb botany to bend in a direction that is continuously moving in a horizontal direction