Yellow wood sorrel
Oxalis corniculata

Herb with branches erect or ascending, sometimes creeping, to 30 cm long, sparsely to densely hairy, with spreading hairs; roots fibrous and branching, sometimes with a taproot.

Leaves cauline, 3-foliolate; leaflets obcordate, bilobed, sinus to two-fifth the length of leaflet; lobes slightly obovate, 4–13 mm long, 24–11 mm wide, with lobe apices rounded and 3–15 mm apart; petiole 3–6 cm long; stipules usually conspicuous; apex ± truncate.

Inflorescences 1–6-flowered. Petals 6–7 m long, yellow.

Fruit ± erect, usually on deflexed pedicels, not held above the leaves, long and usually slender-cylindrical, 8–16 mm long, 1.5–3 mm diam.; outer surface with simple retrorse hairs; seeds ribbed.