views updated May 29 2018

Oxalis (family Oxalidaceae) A genus of annual or perennial herbs that have alternate, palmate leaves without stipules. There are 1 to many leaflets. The flowers are regular, bisexual, and usually solitary, with 5 free and persistent sepals and 5 petals, often fused at the base. There are 10 stamens. The superior ovary is composed of 5 fused carpels, each with a separate style. The fruit is a capsule. Oxalis species are known for their characteristically clover-like leaves (e.g. O. acetosella, wood sorrel), and in many species the leaflets fold down at night. Several species are cultivated. Some can be eaten but others are troublesome weeds (e.g. O. pes-caprae, Bermuda buttercup, which is a weed of the bulb fields of the Scilly Isles, Great Britain). There are about 500 species, found throughout the temperate and tropical regions of the world, but centred on S. Africa, and Central and S. America.