<a href="//commons.wikimedia.org/wiki/Category:Populus_tremuloides" title="Category:Populus tremuloides">Quaking aspen (<i>Populus tremuloides</i>)</a>, backlit fall-colored leaves, showing the flattened petioles that let the leaves hang downward and "quake" in slight breezes.  
<ul><li>At 2,448 m (8,031 ft) along Upper Rock Creek Rd, near John Muir Wilderness, in Mono County, California.</li></ul>
<a href="//commons.wikimedia.org/wiki/User:Dcrjsr" title="User:Dcrjsr">Dcrjsr</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>