WOOD-SORREL FAMILY. Oxalidaceae.

Not a large family, mostly tropical. Ours are low herbs, with sour juice, often with rootstocks or scaly bulbs; leaves with three or several leaflets; flowers perfect; sepals five, often unequal; petals five, stamens ten to fifteen; ovary superior, five-celled, the five styles usually separate; fruit a capsule, containing several or many seeds. By some botanists this is merged in the Geranium Family.

There are many kinds of Oxalis. The Greek name means "sour," in allusion to the sour taste of these plants, which contain oxalic acid. The leaves are alternate, at nightfall the leaflets droop and fold together; the stamens are ten, five long and five short, all with anthers, with filaments broadened and united at base.

Yellow Wood-sorrel Óxalis corniculàta Yellow Spring, summer, autumn Southwest

A pretty little plant, a few inches tall, more or less downy all over, with very slender, reddish, branching stems and light green leaves, about an inch across and thin in texture. The flowers are over half an inch across, with clear yellow petals, often tinged with pale red on the outside, yellow anthers and a green pistil. The capsules are long and downy.

Redwood Sorrel Óxalis Oregàna White, pink Spring Cal., Oreg., Wash.

One of the most attractive of our woodland plants. The succulent, hairy, reddish flower-stalks, about six inches tall, with two small bracts near the top, spring from a clump of root-leaves. The larger leaves are three inches across, with long leaf-stalks, pale and hairy on the under side, rich green on the upper, each leaflet marked with an irregular blotch of pale green. The younger leaves are lighter green than the older ones and in the bud are neatly folded together, the middle leaflet inside the other two. The leaflets fold back, when it is either too hot or too cold to suit the plant. The delicate flowers are about an inch and a half across, white, pale pink, or rose-color, often veined with deeper color and with a spot of yellow at the base of each petal, and well set off by the foliage, which makes patches of rich and variegated green in dense forest shade.

Yellow Wood-sorrel—Oxalis corniculata. Redwood Sorrel—O. Oregana.