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 truly violet, despite the name), 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. 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.