This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Strophostyles umbellata, Britton
Native. Perennial. Propagates by seeds and by rootstocks.
Time of bloom: July to September.
Seed-time: August to October.
Range: New York to Missouri, southward to Florida and Texas.
Habitat: Moist, sandy soil; fields and waste places.
More persistent and troublesome than the preceding species, because perennial. Stems often several from the same rootstock, two to five feet in length, very slender, branched, and trailing. Leaflets smaller and thinner in texture than the preceding species, sparsely hairy, long-ovate to oblong, usually somewhat obtuse at apex and rounded at base, entire, or rarely slightly lobed, the petioles generally shorter than the leaflets, with small, lance-shaped stipules. Flowers in umbellate heads on slender peduncles often three times as long as the leaves, with short pedicels, the corollas pink, fading yellowish, the standard about a half-inch broad. Pods one to two inches long, very slender, straight, slightly flattened, the seeds within closely packed, truncate at the ends, covered with a glandular mealiness.
In cultivated fields, close and persistent hoe-cutting throughout the growing season, in order to prevent seed development and starve the rootstocks. Grazing off when in grasslands, particularly with sheep.