Oxalis smalliana

Oxalis smalliana, commonly known as redwood sorrel or California wood sorrel, is a species of the wood sorrel family, Oxalidaceae, in the genus Oxalis native to moist coast redwood forests of western North America from Monterey County, California to Curry County, Oregon.

The name O. smalliana was proposed over a century ago to describe a primarily Californian wood sorrel species distinguishable from the O. oregana type by flower size and color, but recognition of the taxon faded over time. A 2022 study by Brinegar provided substantial genetic, morphological, and phenological support for its reinstatement as a separate species from Oxalis oregana.