the tiny native sorrel of NZ's lawns and path edges

Size
Height: 5–10 cm
Lifespan
2–3 years
Diet
Not applicable (herb). Photosynthetic.
Habitat
Damp forest, forest margins, stream banks and shaded sites. Prefers moist, well-drained soils with partial to full shade. Often forms small colonies in damp, shaded areas.
Range
Throughout New Zealand from Northland to Stewart Island. Most common in damp forest and shaded areas. Also found in Australia and the South Pacific.
Endemism
Endemic
Main Threats
Habitat loss from land clearance is the primary threat. Competition from introduced weeds. Climate change affecting forest habitats.
Population
Populations are considered stable and widespread. The species is common in damp forest throughout New Zealand. It is threatened by competition from introduced weeds.
Conservation Status
Not Threatened
Human Risk
caution
Handling Note
contains oxalic acid, ingestion causes mild gastric irritation
Conservation Note
Endemic herb; widespread in damp forests and shaded habitats throughout New Zealand.
Assessment
NZTCS Vascular Plants (2023)
Te Ao Māori
In Māori tradition, native wood sorrel was used as a flavouring herb. The sour leaves were added to food. The plant was also used medicinally. The small size meant it was gathered in quantities. The sharp flavour was appreciated as a contrast to bland foods. It was a plant of the damp forest, gathered by those who knew the taste of the wild, a small sour leaf in the shade of the trees, a bright flavour in the dark forest.
A small, creeping herb with clover-like leaves that have a sharp, sour, lemon-like flavour due to oxalic acid. They can be used sparingly in salads, sauces and as a garnish. It is smaller than the native sorrel (Oxalis magellanica). The small, yellow flowers appear in summer. It grows in damp, shaded forest throughout New Zealand. The leaves are divided into three heart-shaped leaflets, similar to clover. They are bright green and sometimes have purple markings underneath. The sour flavour comes from oxalic acid, which is also found in spinach and rhubarb. The leaves should be eaten in moderation, as large amounts of oxalic acid can interfere with calcium absorption. The flowers are small and yellow, with five petals. They appear in summer and are followed by small, capsule-like fruits that contain the seeds. The seeds are dispersed by ants, which are attracted to a fatty structure on the seed coat. Native wood sorrel is a plant of the damp forest understorey. It grows in shaded, moist sites, often on the banks of streams or in the shelter of larger plants. It forms small colonies, never becoming aggressive or weedy. To find native wood sorrel is to walk the damp forest floor. Look for the small, clover-like leaves, the yellow flowers. Taste a leaf and feel the sour tang. It is a small plant, but it has a big flavour. A few leaves can add a lemon-like brightness to a salad or a sauce. It is the wood sorrel of the forest, the sour of the shade.