Diario de artofexplora

I photographed this Western Blue Flag specimen while hiking in the foothills near NCAR in Boulder in June, 2019.

There are two Iris species in Colorado, Iris missouriensis and Iris pseudacorus. The two species can be distinguished by their flower color, with Iris missouriensis having purple, blue-purple or (occasionally) white flowers and Iris pseudacorus having yellow flowers.

Iris missouriensis is common in moist meadows, along creeks and streams, and in aspen groves. In Colorado, the species can be found in the western two-thirds of the state and occurs at elevations in the range of 5,200 and 11,000 feet. Flowers from May to August.

Another common name for Iris missouriensis, one which I've seen used more often locally, is the Rocky Mountain Iris.

Source: Ackerfield, Jennifer. Flora of Colorado. BRIT Press, 2015. pp. 505.