There are 5 or 6 (4 – 8) genera and 250 to 900 species most in Oxalis (500 – 800).

Biophytum, Dapania, Oxalis and Sarcotheca are 4 of the genera.
Lotoxalis, Sassia and Xanthoxalis are seen as separate genera or included in Oxalis.
The genus Averrhoa is usually included in Oxalidaceae but sometimes in Family Averrhoaceae.
Averrhoa are small shrubs or trees.
All the rest are annual or perennial herbs that regrow from bulbs, tubers or corms.

The herbaceous or fleshy leaves are alternate in a spiral.
They are on stalks and there are usually no stipules.
Leaves are palmate or pinnate, often trifoliate and rarely a single leaf.
Leaflets have a pulvinus and they close in the dark.

Axillary inflorescences are solitary flowers or clusters.
The flowers, with parts in 5’s, are usually on stalks.
The 5 sepals can be separate or joined at the base.
The 5 overlapping petals are usually separate but sometimes slightly joined at the base.
The petals sometimes have clawed (narrowed) bases.

There are 5 stamens or 10 in 2 whorls of 5.
When in 2 whorls the outer stamens are shorter.
The filaments are free or the bases are fused.
Anthers are dorsifixed and open inwards via longitudinal slits.
There are often nectaries at the bases of the outer stamens.
There are sometimes 5 infertile staminodes outside the fertile stamens.

The superior ovary has 5 (3) carpels, usually joined but sometimes separate.
There are 5 (3) locules each with 2 to 15 ovules.
There are 5 mostly fused styles and 5 stigmas that are capitate or sometimes bilobed.

The fruit are loculicidal capsules, or sometimes fleshy berries.