Oxalis corniculata

Oxalis corniculata, the creeping woodsorrel, also called procumbent yellow sorrel or sleeping beauty, resembles the common yellow woodsorrel, Oxalis stricta. It is a somewhat delicate-appearing, low-growing, herbaceous plant in the family Oxalidaceae. It has a narrow, creeping stem that readily roots at the nodes. The trifoliate leaves are subdivided into three rounded leaflets and resemble a clover in shape. Some varieties have green leaves, while others, like Oxalis corniculata var. atropurpurea, have purple. The leaves have inconspicuous stipules at the base of each petiole. The fruit is a narrow, cylindrical capsule, 1–2 cm (0.4–0.8 in) long, and noteworthy for its explosive discharge of the contained seeds, 1 mm (0.04 in) long. Pollen is about 34 microns in diameter. This species probably comes from south-eastern Asia. It was first described by Linnaeus in 1753 using specimens from Italy, and it seems to have been introduced to Italy from the east before 1500. It is now cosmopolitan in its distribution and is regarded as a weed in gardens, agricultural fields, and lawns. The leaves of woodsorrel are quite edible, with a tangy taste of lemons. A drink can be made by infusing the leaves in hot water for about 10 minutes, sweetening and then chilling. The entire plant is rich in vitamin C. Any woodsorrel is safe in low dosages, but if eaten in large quantities over a length of time can inhibit calcium absorption by the body.