Violet Wood Sorrel
A low herb with many flowers. Flowers in umbellike groups on long stalks, much higher than the leaves, 5-petaled, light magenta or lavender, rarely white (but never violet), showy. Blooms April-July, also September-November. Leaves trifoliate (like clover), the leaflets heart-shaped, able to close along the central vein, often with purplish markings. Fruit a fairly long, upright capsule, surrounded by the calyx.
Similar species: Missouri has 4 native and 1 introduced Oxalis species, and this is the only one that has magenta or lavender flowers, has leaves that arise only from the base of the plant, and grows from a bulb. The other species all have yellow flowers, leaves along the stem, and no bulbs.