This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Annual or winter annual. Propagates by seeds.
Time of bloom: June to August.
Seed-time: July to September.
Range: Throughout eastern United States and Canada.
Habitat: Cultivated ground; grain and clover fields. Prefers dry soil, and is sometimes grown on such land as a forage plant for sheep.
So rapid is the growth of this weed that a field of young turnips or carrots may be swiftly smothered by it; young grasses and clovers, too, sometimes find it too aggressive.
Stems six to eighteen inches tall, slender, erect, bright green, branching from the base, growing from slender, branching roots. Leaves one to two inches long, linear or awl-shaped, apparently whorled at the joints of the stem but really growing in two opposite clusters of six to eight, with small stipules between. Flowers in terminal cymes; calyx of five sepals, persistent; petals white and longer than the sepals, open only in sunshine; stamens five or ten; styles five. The thread-like pedicels droop as soon as the seed begins to form. Pod or capsule with five valves, which are opposite the sepals. Seeds many, dull black, small, round, flat, sharply margined, roughened with very minute pimples; they are a frequent impurity of grass and clover seed; also they possess long vitality when lying dormant in dry soil. (Fig. 88.)
Fig. 88. - Corn Spurry (Spergula arvensis). X 1/4.
Prevent seed development. In some cases ground infested with Spurry may profitably be grazed off by sheep while the plants are young. Among crops in which hoe-cutting is impracticable, a five-per-cent solution of Copper sulfate, applied when the plants are about half-grown or even when they are in first bloom, will prevent the formation of seed. Land fouled with seeds of Spurry should be put to a well-tilled hoed crop before being seeded with grain or clover.