Oxalis oregana

Oxalis oregana (Redwood Sorrel or Oregon Oxalis) is a species of herbacious plant in the Oxalidaceae family. It is native to the Coast Redwood and Douglas-fir forests of western North America, from British Colombia in Canada, down to California of the United States.

It is a herbacous perrenial plant with erect flowering stems that stand 5-15 cm tall. The tree leaflets are heart-shaped 1-4.5 cm long, with purplish undersides. The inflorescense is 2.4-4 cm in diameter, white or pink, with five petals and sepals. There are 5-chambered seed capsules, which are egg-shaped and hairy, 7-9 mm long. The seeds themselves are shaped like almonds. The redwood sorrel goes through photosynthesis at low levels of ambient light (1/200th of full sunlight). When direct sunlight strikes the leaves, they fold downward, and when in shade again, they reopen.

The leaves of this species were eaten by Native Americans, but probably in small quantities, due to the oxalic acid inside.