Yellow woodsorrel Oxalis stricta L.
Family: Oxalidaceae (Woodsorrel family)
Life cycle: Perennial/annual depending upon climate
Native status: Native to N. America
Habitat: Poorly maintained turf; waste areas
General description: Young plants are erect, but as age they become spreading. Leaves are light-green, trifoliolate with heart-shaped leaflets. Yellow flowers with five petals; fruit is a 5-ridged, cylindrical capsule up to 0.6 inch long. Spreads by seeds and rhizomes.
Key ID traits: Light-green, heart-shaped leaflets on trifoliolate leaf.
Similar species: Yellow woodsorrel is often mistaken for a legume because of the trifoliate leaves resembling those of clovers. However, yellow woodsorrel lacks stipules on the base of petioles, a characteristic of the trifoliolate legumes (clovers; black medic) and it has heart-shaped leaflets.
Miscellaneous: Leaves fold up at night. Plants have a lemony flavor, and are often used in salads. The flavor is due to oxalic acid. The seed capsules ‘explode’, dispersing seed distances greater than 10 feet.