Native. Perennial. Propagates by seeds. Time of bloom: June to September. Seed-time: August to October. Range: Ohio to Illinois, southward to Florida, Arkansas, and Texas. Habitat: Wet meadows, banks of streams, and ditches.
Stem ten to twenty inches tall, rather stout, smooth, four-sided, sometimes simple and erect or often diffusely branched, the branches spreading, the lower ones decumbent. Leaves one to three inches long, opposite, their bases connected by bristly, membranous stipules, entire, elliptic, pointed at each end, with smooth surface but rough edges. Flowers in dense terminal and axillary whorled clusters, the corollas funnel-form, four-lobed, white, less than a quarter-inch long; stamens four, inserted on the tube; style two-cleft; calyx also four-lobed, its acute teeth persistently crowning the fruit, which is two-celled'; when ripe the carpels separate, one carrying with it the partition, leaving the other bare on the inner face. Seeds small, hard, black, oblong to wedge-shaped, rounded on the back, with flat inner face; too often an impurity of southern grass and clover seed. (Fig. 278.)
Fig. 278. -Smooth Buttonweed (Spermacoce glabra). X 1/4.
Sow clean seed. Harvest infested meadows before the flowers mature, particularly if the hay is intended for market. Ground badly fouled with the weed should be put under cultivation for the purpose of destroying its perennial roots. Good drainage is a discouragement to the growth of this plant, for it prefers the soil damp.