Oregon woodsorrel

Oxalis oregana is a short, herbaceous perennial with erect flowering stems 5–15 cm tall. The three leaflets are heart-shaped, 1–4.5 cm long with purplish undersides, on 5–20 cm stalks. The inflorescence is 2.4–4 cm in diameter, white to pink with five petals and sepals. The hairy five-chambered seed capsules are egg-shaped, 7–9 mm long; seeds are almond-shaped. It spreads by a scaly rhizome varying the size of patches. They can be seen throughout moist forest under-canopies. The species ranges from southern Humboldt County, California to southwestern British Columbia. Unlike its close relative Oxalis smalliana, O. oregana consistently has white flowers and shows typical single sequence haplotypes in genetic analyses. In areas where both species overlap, O. oregana reaches peak flowering approximately one month later than O. smalliana.

The leaves of Oxalis oregana are eaten by the Cowlitz, Quileute and Quinault peoples. Like spinach, they contain mildly toxic oxalic acid, which is named after the genus. They are safe to eat in small amounts for those with no oxalate-related conditions.