The name is derived from the Greek word oxalis ("acid") because the plants have an acidic taste. The plant has inversely heart-shaped leaflets in clover-like arrangements of three. The leaves often fold along the center crease. The erect seedpods and their bent stalks form a sharp angle. The yellow flowers are sometimes reddish at the base. It grows to a height of 6 to 15 inches. It can be found in dry soil and roadsides. It blooms from May to October.

The Yellow Wood Sorrel is common in the Clinch Mountain area.

Sources:
"A Field Guide to Wildflowers, Northeastern and North-central North America" by Roger Tory Peterson and Margaret McKenny
Encyclopaedia Britannica

Photo taken behind my house