This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual or perennial. Propagates by seeds.
Time of bloom: July to September.
Seed-time: August to October.
Range: Nova Scotia to Manitoba, southward to Florida and Texas. Habitat: Damp meadows, pastures, and waste places.
Stem six to eighteen inches long, rather weak and flaccid, decumbent, branching from the base, four-angled, often reddish. Leaves a quarter-inch to an inch long, narrowly ovate to oblong, obtuse, entire, partly clasping, five-nerved, minutely specked with the pellucid dots. Flowers in terminal cymose clusters, each about a quarter-inch broad, bright yellow or light orange, the pedicels subtended by awl-like bracts. Capsules pointed ovoid, about a sixth of an inch long, filled with seed of dust-like smallness. The plants often turn reddish in autumn and their presence is then noted where they had not been suspected.
Cultivate and heavily fertilize the ground; the presence of this plant is considered by many farmers to be an indication that the soil lacks lime. Follow the cultivated crop with clover.