Northern Prairie Wildlife Research Center
The distribution of prairie spiderwort is largely determined by the dry sandy soils it prefers. In North Dakota, most collections have been in the Sheyenne Delta, the Towner area, and in counties south and west of the Missouri River. Elsewhere, the species ranges west to the Rocky Mountains and south to Texas and Arizona at elevations under 8,000 ft.
Prairie spiderwort is a smooth, subsucculent, perennial monocot up to 20 inches tall. Stems are often tufted, and when pulled apart, the copious mucilaginous slime inside forms what somewhat resembles a spider's web. The narrow leaves are up to a foot long, folded into a V-shape, and have long sheaths. Clusters of up to 25 bright blue-to-rose or lavendar flowers form on the ends of the main stems or branches. Each flower is borne on a thin pedicel. There are only three sepals and petals; the latter regularly wither by mid-day into a soft, inky mass. Fruits are rounded capsules containing 2-6 flattened, pitted seeds.
Look for prairie spiderwort through August on sandy native prairie. Grazing pressure, unless extremely intense, does not seem to have much effect on the abundance of the plant. Young stems and leaves of prairie spiderwort are occasionally mentioned as being useful for edible greens and potherbs. A cultivated variety called "Rubra" has red flowers.
This plant is a member of the largely tropical spiderwort family (Commelinaceae), the name dedicated to a family of 17th century Dutch botanists named Commelin. The generic name was dedicated to John Tradescant, gardener to Charles I of England. The specific epithet occidentalis means "western" in botanical Latin. The plant was first described for science by Nathaniel Lord Britton (1859-1934), long time Director of the New York Botanical Garden, and placed in its current, accepted taxonomic position in 1899 by the eminent curator of the State Museum of Kansas Bernard Bryan Smyth (1843-1913).