Shasta knotweed (Polygonum shastense), branches with white, brownish-green-streaked flowers. Various individual flowers show the 5 separate petals, the 5 to 8 stamens, and the triangular, 3-style-tipped pistil.  At 10,380ft along trail between Saddlebag and Steelhead Lakes in 20-Lakes Basin, Hoover Wilderness, Sierra Nevada mountains, California USA.
<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>