Oxalis

Oxalis floral diagram

Oxalis acetosella jfg

Lyc oviposit

Close-up of an 'apricot' NZ yam

Oca

Oxalic acid

Oxalis is a large genus of flowering plants in the wood-sorrel family, Oxalidaceae. It is one of the largest genera in the family, with over 800 species distributed around the globe. The name Oxalis is derived from the Greek word for "sour," referring to the sour taste of the leaves and stems, which is due to the presence of oxalic acid. This characteristic makes them easily recognizable and gives them their common name, wood-sorrel, not to be confused with true sorrels which belong to the genus Rumex within the family Polygonaceae.

Description

Oxalis species can vary widely in their appearance. They are mostly herbaceous plants, but some are shrubs. They can be perennial or annual, with some species forming bulbs or rhizomes. The leaves of Oxalis are typically trifoliate, resembling a clover, though some species have more or fewer leaflets. The flowers of Oxalis are generally small, with five petals that can be yellow, white, pink, or purple.

Distribution and Habitat

Oxalis species are found worldwide, with the highest species diversity in tropical South America and southern Africa. They inhabit a wide range of habitats, from forests and grasslands to alpine regions and deserts. Some species have become widespread weeds, thriving in gardens, lawns, and agricultural fields, as well as in natural areas.

Cultivation and Uses

Several Oxalis species are cultivated as ornamental plants for their attractive foliage and flowers. Oxalis triangularis, with its striking purple leaves, and Oxalis acetosella, known for its delicate white flowers, are popular in gardens and as houseplants. Despite their beauty, care must be taken as some species can become invasive outside their native range.

In addition to their ornamental value, some Oxalis species are edible, with the leaves adding a lemony tang to salads and other dishes. However, due to the presence of oxalic acid, which can be toxic in large quantities, they should be consumed in moderation.

Ecology

Oxalis species play a role in their ecosystems as a source of food for various insects and animals. However, their rapid growth and ability to reproduce through both seeds and vegetative means can allow them to dominate and alter native plant communities, particularly in regions where they are introduced species.

Conservation

While many Oxalis species are common and not of conservation concern, there are some that are rare and endangered in their natural habitats. Habitat destruction, invasive species, and climate change are threats that can impact the survival of these species. Conservation efforts are necessary to protect the diversity within the genus.

See Also

• Oxalic acid
• Herbaceous plant
• Perennial plant
• Annual plant
• Invasive species