Creeping woodsorrel
Oxalis corniculata
Family · Oxalidaceae · Irritating
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The little clover-leaved plant with a sour taste that grows in pavement joints and everyone's flowerpots, flowering all year. It is the same acidity as Bermuda buttercup, and the same warning.
Town and roadside · Walls and rocks · Fields and pasture · Roadsides and waste ground
Also known asprocumbent yellow sorrel, sleeping beauty
How to tell it
A creeping plant rooting at the nodes. Leaves of three inverted-heart leaflets, often stained wine red. Small yellow five-petalled flowers in groups of two to five. The capsules are upright cylinders that burst at a touch and shoot the seeds out.
What it is confused with
Bermuda buttercup
Oxalis pes-caprae
Bermuda buttercup is much larger, carries big flowers in an umbel atop a leafless stalk and grows from a bulb; this is small, creeping and roots at the nodes. Both hold the same oxalic acid and the same limit.
Open sheet →What it is for
Traditionally used as a souring agent in the smallest amounts, like the other wood sorrels. It contains oxalic acid, which in quantity binds calcium and aggravates kidney trouble: a curiosity seasoning, never a salad.
Traditionally used as food. This is not permission to eat it.