Oxalis oreganum, or ‘Redwood Sorrel’, is a perennial species born from scaly rhizomes. The brown, pubescent, flowering stems stand 5-15 cm tall producing flowers with five white petals with red veins that are 12-20 mm long. The ten stamens of the flower are of two unequal lengths. Leaves are borne on separate, basal stems that stand 5-20cm tall. The leaves are compound and clover-like consisting of three heart shaped and folded leaflets. In dim forest understory, the leaflets are held horizontally to maximize interception of light, creasing the leaflets sharply down during instances of direct sunlight or at night; taking 6 minutes to fold up and 30 minutes to flatten out. It is thought that this is done to conserve water, but folding is also observed done in rain reducing the impact of falling droplets. The fruit is a football shaped capsule with five chambers and is 7-9 mm long with corrugated, almond shaped seeds. This species is typically found in moist, forested sites at mid to low elevations and is common in Oregon.
Historically ‘Redwood Sorrel’ was eaten by Native Americans, the leaves possessing a sour, tangy taste due to the oxalic acid inside which can be potentially harmful.
Pojar, J. and A. McKinnon (1994) Plants of the Pacific Northwest Coast. Lone Pine Publishing, Washington, Canada.