Atragene occidentalis or Clematis occidentalis
(Western Blue Virginsbower)
Family:
Ranunculaceae (Buttercup)
  
Atragene occidentalis is a creeping or climbing, slightly woody vine. The flowers lack true petals but have four light blue sepals that look like petals. Leaves are trifoliate, with three rather large leaflets.

Vegetation zone:  Foothills, Montane, Subalpine
Time of bloom:  May - July
Origin:  Native
Eastern Colorado Wildflowers