Name from oxus, sour, in allusion to the taste of the foliage.

Annual or perennial by subterranean shoots. Naturalized from Europe. Roadsides, fence corners, and waste places. Everywhere. May-October.

Root

Fibrous, sending out underground stolons which run to a considerable distance and throw up new plants.

Stem

Pale green, at first erect, leafy, branching, finally spreading or prostrate, six to twelve inches high.

Leaves

Compound, of three heart-shaped leaflets meeting at the point.

Flowers

Bright yellow, in a three to five-flowered, loose cluster at the head of the stalk, open only in sunlight.

Calyx

Sepals five, lanceolate, persistent.

Corolla

Petals five, bright yellow, commonly reddish at the base, spreading, longer than the sepals.

Stamens

Ten; filaments broad, somewhat united at the base.

Pistil

Ovary five-celled; styles five.

Fruit

Capsule, five-celled, slender; seeds many.

This is one of our most persistent bloomers. It begins in May and never stops until late September; often continues well into October. The plant is everywhere, always coming up in flower-beds. The branching stem frequently gets more than a foot high, is leafy, and the foliage a pleasant acid to the taste.

Yellow Wood Sorrel. Oxalis stricta

Yellow Wood-Sorrel. Oxalis stricta

The leaf is compounded of three broad, heart-shaped leaflets with their points united at the tip of the slender leaf-stem. These droop and fold together at night or when it rains. The bright golden flowers rise with the sun and set with it. They are happy only in sunshine. The plant is variable.