Oxalidaceae, the Wood Sorrel Family
Herbs, with alternate or basal compound leaves with 3 reverse heart-shaped leaflets; sepals, petals, and styles each 5; stamens 10. (Wood Sorrel)
| 1a. Leaves all basal; flowers white to pink-purple (1-2 dm. high; late spring) — 2. | |
| 1b. Stem-leaves present; flowers yellow (1-5 dm. high; spring and summer) — 3. | |
| 2a. Flower-stalks bearing a single flower | Wood Sorrel, Oxalis acetosella. |
| 2b. Flower-stalks bearing an umbel of several flowers | Wood Sorrel, Oxalis violacea. |
| 3a. Stem prostrate and creeping Wood Sorrel, Oxalis repens. | |
| 3b. Stem erect or ascending — 4. | |
| 4a. Pedicels with spreading pubescence | Wood Sorrel, Oxalis corniculata. |
| 4b. Pedicels with appressed pubescence | Wood Sorrel, Oxalis stricta. |