quaking : Idioms & Phrases

• noun Old World aspen with a broad much-branched crown; northwestern Europe and Siberia to North Africa
  Populus tremula; European quaking aspen.
  

WordNet

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

Webster 1913

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

Webster 1913

• . (Bot.) (a) 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; B. media and B. minor are the smaller kinds. (b) Rattlesnake grass (Glyceria Canadensis).

Webster 1913