Quaking

Quaking aspen — an American species of poplar (Populus tremuloides), the leaves of which tremble in the lightest breeze. It much resembles the European aspen. See Aspen.

Quaking bog — a bog of forming peat so saturated with water that it shakes when trodden upon.

Quaking grass — One of several grasses of the genus Briza, having slender-stalked and pendulous ovate spikelets, which quake and rattle in the wind. Briza maxima is the large quaking grass; Briza media and Briza minor are the smaller kinds.