Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout most of North America.
Habitat: In shallow water and on muddy shores, and in other wet places in the valleys and plains.
Growth Duration: Annual
Conservation Status: Not of concern
Fibrous-rooted annual, the stem simple or branched, erect or diffuse, 1-3 dm. tall, usually with stalked glands upward.
Leaves opposite, sessile, entire or with a few small, sharp teeth, 1-4 cm. long and 2-15 mm. wide, on pedicels 1-3 cm. long.
Flowers solitary, on long pedicels arising in the axils of reduced upper leaves; calyx of 5 distinct sepals, 3-7 mm. long, closely subtended by a pair of sepal-like bracteoles, these and the sepals narrow; corolla tubular, bilabiate, 7-10 mm. long, the tube white or yellowish, the limb purplish, the upper lip slightly notched, the lower 3-lobed; fertile stamens 2, the others wanting, the pollen sacs parallel on a flattened surface inside the corolla tube.
Capsule dehiscing by 4 valves, ovoid, pointed, 5-7 mm. long.