Western White Clematis or Clematis ligusticifolia

"Clematis ligusticifolia" is a climbing, spreading vine with showy flowers. It is also known as old-man's beard, yerba de chiva, and virgin's bower,. It is native to North America where it is widespread across the western United States in streamside thickets, wooded hillsides, and coniferous forests up to 8,500 feet.