is (in the West) the only iris species east of the Sierra Nevada and the Cascades, and so is easily identified over most of its range. The long, linear, upwards-pointing leaves grow only at the base; the leafless stems rise to heights of up to 20 inches - similar to the longest leaves - and usually bear one or two flowers (occasionally up to four).
Flowers are blue to pinkish purple, consisting of 3 large, oblanceolate sepals (over 2 inches long), curved backwards, between which are 3 somewhat shorter petals, more upright. Sepals often have yellowish patches at the center, and a purple veined pattern around the edge. The middle of the flower contains a group of stamens and a branched style.