Horticulture/Oxalis corniculata

Creeping wood sorrel (Oxalis corniculata), also known as yellow wood sorrel and procumbent yellow sorrel, is a somewhat delicate-appearing, low-growing, herbaceous plant in the family Oxalidaceae. It is commonly found as a weed of lawns, gardens, and pathways.

Description
This woodsorrel is a low-growing, herbaceaous plant with a narrow, creeping stem that readily roots at the nodes. The trifoliate leaves are subdivided into three rounded leaflets and resemble a shamrock. Some varieties have green leaves, while others have purple leaves, like the Oxalis corniculata var. atropurpurea shown in the photo. The leaves have inconspicuous stipules at the base of each petiole.

The fruit is a narrow, cylindrical capsule, 1 to 2 cm long and noteworthy for its explosive discharge of the contained, 1 mm long seeds.

Ecology
This species is cosmopolitan in its distribution, and its place of origin is unknown. It is regarded as weed in gardens, agricultural fields, and lawns.

Uses
The leaves of wood sorrel are edible, having a tangy taste. 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. Although wood sorrel is safe in low dosages, it can inhibit calcium absorption by the body if eaten in large quantities over a length of time.

Control
Control of this plant can be difficult because it can grow back from small stem and root fragments.