Wood Sorrel or False Shamrocks

Description:

Oxalis /ˈɒksəlɪs/ is a large genus of flowering plants in the wood-sorrel family Oxalidaceae comprising about 570 species. The genus occurs throughout most of the world, except for the polar areas; species diversity is particularly rich in tropical Brazil, Mexico and South Africa. Some species are called yellow sorrels or pink sorrels after the color of their flowers instead. Other species are colloquially known as false shamrocks, and some called sourgrasses.

Habitat:

Growing on the creek-bank behind my house.