"Sour-grass", the children call the leaves of yellow oxalis, or call the seeds "pickles" and gather them for doll feasts or for brief refreshment during play. For the yellow wood-sorrel is not truly a woodland species, bu1 comes into pastures, gardens, and Lawns where the soil is somewhat acid, blooms its bright buttercup-yellow Glowers and makes innumerable tat green seeds. Like the other members of the wood-sorrel family, the entire plant is acid. The bright green leaves are three-parted, each section heart-shaped. It is said that the original Irish shamrock was an oxalis with this same plan of leaf.
Oxalis stricta L.
April - June Lawns, gardens.
Yellow wood-sorrel begins to bloom in April and continues to blossom steadily during most of the summer, seeds itself, and sends up a new crop of plants before the season is over. There are several species which hear yellow flowers, as well as the more rare violet wood-sorrel and the white oxalis. The latter is a plant of the cool northern bogs and moist, mossy, coniferous woods; the violet wood-sorrel of Illinois oak woods and rocky places from Massachusetts to Minnesota and southward, while the yellow prefers sunny, sandy soil.
There are two yellow-flowered sorrels in Illinois that are often con-fused. Oxalis stricta is often found in open fallow fields and pastures but sometimes comes into open woods. It is usually branched at the base and its capsules are finely pubescent. The common yellow wood-sorrel (Oxalis cymosa), has Bowers similar to the above species, but does not branch near the base and i- strictly a woodland plant. It is often two feet tall with scattered lowers followed by nearly smooth capsules.