Oxalis pes-caprae (Bermuda buttercup, African wood-sorrel, Bermuda sorrel, Buttercup oxalis, Cape sorrel, English weed, Goat's-foot, Sourgrass, Soursob, Soursop and in Hebrew ????? ????) is a species of tristylous flowering plant in the wood sorrel family Oxalidaceae. Oxalis cernua is a less common synonym for this species.

The flower is actinomorphic, with a calyx composed of five free or slightly fused sepals, a sympetalous corolla composed of five fused petals, an apoandrous androecium composed of ten free stamens in two ranks, and a compound pistil.

Indigenous to South Africa, Bermuda buttercup is a highly invasive weed in many parts of the world including the United States (particularly coastal California), Europe, Israel and Australia.[1] It is often called by the common name sourgrass or soursob due to its pleasant sour flavor. This sourness is caused by oxalic acid, which is toxic in large quantities and may contribute to kidney stones.