Stem: perennial; 2’ to 3’ tall; unbranched; smooth with waxy, bluish cast on stem and leaves.
Leaves: opposite; lower round-oval, 2” by 1 3/8”, upper slightly chordate, 1” by 1”; sessile to somewhat clasping; smooth above and below.
Inflorescence: raceme with two flowers per node; opposite bracts at each node, 5/8” long, oval.
Flowers: corolla purple to lavender, two-lipped, narrow, funnel-shaped, 1 3/8” long; calyx five-lobed, 5/16” long; flowering from late May to mid-June.
Fruits: capsules; 7/8” long, widest near the base, opening at the tip by four segments; seeds squarish, 3/32” long; fruiting begins in early June.
Habitat: common on Loess Hills prairies in western Iowa; very infrequent elsewhere on dry, sandy prairies and stabilized sand dunes.