Kingdom: Plantae
Division: Magnoliophyta
Class: Eudicotyledoneae
Subclass: Rosidae
(unranked): Eurosids
Order: Oxalidales
Family: Oxalidaceae
Genus: Oxalis 
Scientific name: Oxalis articulata
Common name: Pink sorrelSourgrass, Pink Oxalis

Sourgrass (Oxalis articulata) originates from South America but is now naturalised in many parts of the world. Its a perennial growing to 0.2 m) by 0.1 m. It blooms from early spring or year-round when the climate is mild. It thrives in well-drained soil, full morning/afternoon sun to semi-shade. It’s been reported to tolerate temperatures down to about -5 to -8 ºC. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects.
Leaves and flowers are edible - raw or cooked. A pleasant lemony flavour, they make a nice flavouring in salads. Use in moderation, see warning below.
The leaves contain oxalic acid, which gives them their sharp flavour. Perfectly all right in small quantities, the leaves should not be eaten in large amounts since oxalic acid can bind up the body's supply of calcium leading to nutritional deficiency. The quantity of oxalic acid will be reduced if the leaves are cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.

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On a hot day, the leaves droop.
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Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/

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