This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Oxalis corniculata, L. (Xanthoxalis corniculata, Small)
Native. Annual or perennial. Propagates by seeds and by stolons. Time of bloom: March to late October at the northern limits of range; throughout the year where not snow-covered. Seed-time: Throughout the year. Range: New Jersey to Kansas, southward to the Gulf States and
Mexico. Habitat: Fields, roadsides, waste places.
This plant, like the preceding one, may be called annual, in that it flowers and fruits during its first year of life; but this species prolongs its existence through its many slender runners.
Stems low, with spreading branches, those at the base creeping on the ground, three inches to a foot or more long, rooting at the joints, those above sparsely covered with fine, spreading hairs. Leaflets deep green, sometimes with a purplish tinge, notched at the outer edge, nearly smooth, often an inch broad. Flowers yellow, in umbellate or cymose clusters, peduncle and pedicels sparingly hairy, the latter not deflexed in fruit. Capsule smaller than that of the preceding species, a little more than a half-inch long, faintly five-sided, with tapering point. Seeds compressed ovoid, brown, transversely wrinkled.
Means of control the same as for Wood Sorrel.