Overview: The Oxalidaceae are a family of flowering plants often called the wood-sorrel family. It contains roughly 900 species, predominantly small annual or perennial herbs, with a few shrubs and tree-like members in some lineages. The family name derives from the genus Oxalis, itself named from Greek for "sour" in reference to the acid taste of many species. For general references see family information and broader plant resources at flowering plant guides.

Characteristics

Plants in this family typically have compound leaves, often trifoliolate or pinnate, and many show nyctinastic movements (folding at night). Flowers are usually bisexual, with five petals and sepals and stamens often in multiples of five; symmetry ranges from radial to slightly bilateral. Fruits vary widely between genera — from dry capsules to fleshy fruits — and seeds often have distinctive shapes. For trait databases consult trait resources.

Distribution and habitat

Oxalidaceae species occur worldwide but are most diverse in tropical and subtropical regions; a number of species also thrive in temperate zones. They occupy habitats from forest understories and grasslands to disturbed sites and rocky slopes. Regional floras and distribution maps can be found via regional plant portals.

Uses, ecology and cultural notes

Several oxalidaceous plants are cultivated as ornamentals for their colorful foliage and delicate flowers; some, notably in the genus Averrhoa, produce edible fruits cultivated commercially in the tropics. The characteristic sour taste comes from oxalic acid and related compounds; this has led to food uses, traditional remedies and also concerns about overconsumption. Ecologically, many species provide nectar and pollen for insects and serve as groundcover in shaded habitats. Further reading: horticulture notes and ethnobotany summaries.

Taxonomy and notable genera

The family belongs to the order Oxalidales. Well-known genera include Oxalis (wood-sorrels), which contains most species, and Averrhoa (starfruit and bilimbi). Other smaller genera and taxonomic treatments can be explored through specialist keys and academic summaries at taxonomic resources.

  • Key features: sour taste, compound leaves, 5-parted flowers
  • Habit: mainly herbs; some shrubs and small trees
  • Importance: ornamentals, edible fruits, ecological groundcover