Growing from a corm, the prairie iris is 1–2 feet tall and is usually unbranched. It has leaves 1 1/2–2 feet long by 1 inch wide. Most of them grow from the base and are conspicuously veined, clasp the stem directly at the base, and are folded (pleated) for most of their length. The flowers grow in a cluster at the end of the stem and open one at a time for several days in succession. They are cup-shaped to flat. The 3 outer tepals are spreading, about 1 1/2 inches wide, light to deep purple; the 3 inner tepals are dwarfed, cupped or crimped, and usually a deeper purple. The inner portion of the tepals is yellowish, spotted with reddish-brown.
A member of the iris family (family Iridaceae) which consists of herbs growing from rhizomes, bulbs, or corms, with narrow basal leaves and showy clusters at the tips of long stalks. There are about 60 genera and 1,500 species, distributed in temperate and tropical regions. Among them, Iris, Freesia, Gladiolus, Bugle Lily, and Montbretia are popular ornamentals. Saffron dye is obtained from Crocus, and essence of violets, used in perfumes, is extracted from the rhizomes of Iris.
The species name of this plant is named for Thomas Drummond, (ca. 1790-1835), naturalist, born in Scotland, around 1790. In 1830 he made a trip to America to collect specimens from the western and southern United States. In March, 1833, he arrived at Velasco, Texas to begin his collecting work in that area. He spent twenty-one months working the area between Galveston Island and the Edwards Plateau, especially along the Brazos, Colorado, and Guadalupe rivers. His collections were the first made in Texas that were extensively distributed among the museums and scientific institutions of the world. He collected 750 species of plants and 150 specimens of birds. Drummond had hoped to make a complete botanical survey of Texas, but he died in Havana, Cuba, in 1835, while making a collecting tour of that island.