Wood Sorrel
Oxalis acetosella
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Shamrock-shaped leaves that fold down flat at night and in bright sun.
A delicate, low woodland perennial with trefoil leaves of three heart-shaped leaflets, bright yellow-green and slightly translucent, and solitary white flowers finely veined with lilac. Wood sorrel grows in shaded, damp, mossy places — the floor of oak and conifer woodland, banks, rotting stumps — and is common in the wooded ground around Dumfries.
Behaviour
The leaflets fold downward against the stalk at night, in heavy rain and in strong sun, a movement driven by changes in water pressure at the leaf base. The plant produces two kinds of flower: showy spring ones for cross-pollination, and later inconspicuous ones that never open and self-fertilise, guaranteeing seed. The leaves taste sharply of lemon, from oxalic acid.
When to see it
Quick facts
- Family
- Wood sorrels (Oxalidaceae)
- Height
- 5–15 cm
- Status
- Native; common in shaded, mossy woodland
Photo by Jörg Hempel, CC BY-SA 3.0 de, via Wikimedia Commons