This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Annual and winter annual. Propagates by seeds.
Time of bloom: July to September.
Seed-time: August to October.
Range: Eastern United States, Maine to Texas; also on the
Pacific Slope. Habitat: Clover fields, meadows, and waste places.
A special pest in clover fields. Stem erect, hairy, one to three feet tall, branching by forking. Lower leaves petioled, two or three inches long, pointed at both ends, the lowermost tapering to hairy petioles; stem-leaves sessile, becoming mere pointed bracts near the top. Flowers in forking, one-sided spikes, sessile or on very short pedicels; petals five, pale pink or white, deeply cleft; styles three, exserted; stamens ten; calyx about a half-inch long, five-ribbed, very hairy, short-toothed. Capsule many-seeded, oblong ovoid, opening at apex by three or six teeth.
Means of control the same as for the Sleepy Catchfly.