quaking aspen

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A North American deciduous tree (Populus tremuloides) having broadly ovate, finely toothed leaves with flattened petioles, which quiver in a light breeze.

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

• noun Populus tremuloides, the American aspen, so called from its leaves whose flattened petioles cause them to tremble in the breeze.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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