Family Oxalidaceae (Wood-Sorrel Family).
Also known as Yellow Wood-Sorrel, Pickleweed, and a number of other names, many of which refer to the sour taste produced by the oxalic acid in the leaves. The tiny yellow flowers pop up in sunny spots everywhere. These plants are quite at home in lawns, gravel, pavement cracks, and anywhere else they can get a foothold. The leaves are like miniature versions of the leaves of their close relative the shamrock. The angled stems of the seedpods distinguish this from the closely related Oxalis corniculata.
Gray describes the genus and the species.
ÓXALIS L. WOOD SORREL. Sepals 5, persistent. Petals 5, sometimes united at base, withering after expansion. Stamens 10, usually monadelphous at base, alternately shorter. Styles 5, distinct. Pod prismatic, cylindric, or awl-shaped, membranaceous; valves persistent, being fixed to the axis by the partitions. Seeds pendulous from the axis, anatropous, their outer coat loose and separating. Embryo large and straight in fleshy albumen; cotyledons flat. —Several species produce small peculiar flowers, precociously fertilized in the bud and particularly fruitful; and the ordinary flowers are often dimorphous or even trimorphous in the relative length of the stamens and styles. (Name from oxys, sour.)
O. strícta L. Pale green, appressed-pubescent or strigose; stems usually several, decumbent, stoutish; stipules evident; pedicels 1-4 (mostly 2), subumbellate at the end of the peduncle, at length deflexed; the fruit large, columnar, short-pointed, 15–23 mm. long. —Dry or sandy soil, s. Me. to Dak, and southw., common. —The petals pale yellow, often with a reddish spot near the base.
