OXALIDACEAE - The Wood Sorrel Family This is a family of around 90 species (or around 900 according to some classifications), mainly of annual or perennial herbs, found mainly in tropical and sub-tropical areas of the world, although some occur in temperate regions. They are mainly grown as ornamental plants, although the tubers and leaves of some species are used as food, and some are considered weeds. The family includes the well-known tropical ground-cover, Oxalis pes-caprae, the Bermuda Buttercup, and Oxalis corniculata, a weed of temperate gardens.

Characteristics of this Plant Family:

Leaves, Stem & Roots ~ The leaves of Oxalidaceae are alternate with no stipules (small leafy growths at the leaf nodes), simple or compound, and often trifoliate like a clover leaf in species of Oxalis. In some species the leaflets fold down at night or in cold weather. The root is fleshy and is sometimes eaten. Some produce bulbils in the leaf axils.

Flowers ~ The flowers have five sepals and five petals, which are sometimes joined at the base and sometimes separate. There are ten stamens in two whorls of five, and five styles, each with an ovary at the base. The flowers may be solitary or in clusters.

Seeds ~ The seedpod forms inside the flower (a superior ovary), and is composed of five sections, each containing several seeds. The seeds of some species have a fleshy aril at the base. To disperse the seed, the inner cells of the aril turn inside out suddenly and separate from the seedcoat, and the seed is catapulted from the plant.

In cold conditions, the European species Oxalis acetosella (Wood Sorrel) may be cleistogamous (can produce viable seeds without opening).

Members of this Family usually have:

Flowers with five petals
Ten stamens in two rings of five
A superior seed capsule with five parts
No stipules

They often have a fleshy aril to fling the seed from the pod
Often have folded leaflets

and are mostly tropical and subtropical annual and perennial herbs