Aconitum columbianum
(Monkshood)
 Family: Helleboraceae (Hellebore) or
            Ranunculaceae (Buttercup)
  
Monkshood is a tall plant growing in moist areas in the mountains. Blue-purple flowers appear in loose racemes at the top of slender stems. Blossoms have a distinctive hooded petal. Leaves are palmately divided with toothed lobes. Plants are poisonous.

Compare to Delphinium barbeyi (Subalpine Larkspur) which also has dark blue-purple flowers, but the blossoms lack a hood.
Vegetation zone:  Montane, Subalpine
Time of bloom:  July - September
Origin:  Native
Eastern Colorado Wildflowers