Iris missouriensis (syn. I. montana) is a hardy flowering rhizomatous species of the genus Iris, in the family Iridaceae. Its common names include western blue flag, Rocky Mountain iris, and Missouri flag. It is native to western North America. Its distribution is varied; it grows at high elevations in mountains and alpine meadows and all the way down to sea level in coastal hills. This species is commonly found growing in wet meadows, seeps, dry steppes, and open woodland. It is the most drought-tolerant of our native irises only needing moisture in the spring.
Iris missouriensis is an erect herbaceous rhizomatous perennial, 20 to 40 cm high, with leafless unbranched scapes (flowering stems) and linear basal leaves, 5 to 10 mm wide, similar in height to the scapes. The inflorescence usually consists of one or two flowers, exceptionally three or four. Each flower has three light to dark blue, spreading or reflexed sepals lined with purple and three smaller upright blue petals. (Wikipedia ) Photo credit: By Walter Siegmund CC BY-SA 3.0