Yellow woodsorrel

Image by: James Altland, USDA-ARS
Yellow woodsorrel has a rounded mound growing habit and green foliage.
Image by: James Altland, USDA-ARS
Image by: James Altland, USDA-ARS
Yellow woodsorrel foliage is trifoliate, with 3 obcordate leaflets with only slight pubescence visible on leaf margins.
Image by: James Altland, USDA-ARS
Image by: James Altland, USDA-ARS
Yellow wood sorrel flowers are yellow with 5 petals and 5 stamens.
Image by: James Altland, USDA-ARS
Image by: James Altland, USDA-ARS
Yellow woodsorrel is the larger and greener leafed plant-creeping woodsorrel is smaller with purple-tinted foliage.
Image by: James Altland, USDA-ARS
Oxalis stricta
Family: 
Oxalidaceae
Life cycle: 
Perennial
Habit: 
Yellow wood sorrel generally grows more upright than other species of Oxalis, forming a large mound 6 to 8 inches tall and wide.
Flowers: 
Flowers on yellow wood sorrel are yellow with 5 petals and 5 stamens and occur in an umbel (cluster). They are approximately ½ inch, and occur in late spring or early summer.
Favorable environments: 
Container
Favorable environments: 
Field
Favorable environments: 
Greenhouse
Favorable environment notes: 
Yellow wood sorrel is commonly found in nursery containers yards, greenhouses, landscapes, and in turf grass and lawn areas. It is well adapted to survive in a variety of exposures and soil types. It prefers sunny, moist, but well drained environments to germinate and grow to maturity.
Dissemination: 
Yellow wood sorrel plants produce seedpods that are erect, cylindrical capsules with a pointed tip usually about 1/3 to 1 inch long. When seeds mature, capsules explode, ejecting seed into the surrounding environment. Seeds are also easily transported on soles of shoes, pots and equipment due to their rough, angled exterior. Yellow woodsorrel also produces rhizomes which are horizontal underground stems. New roots grow from their nodes, down into the soil, and then send up new shoots to the surface.
Of interest: 
In colder areas, it is often referenced as a summer annual. The leaves, flowers and immature seed pods of yellow wood sorrel are edible and have a tangy lemon flavor. However foliage of this plant does contain oxalic acid, which if consumed in large quantities, can be toxic.