This native annual plant branches frequently at the base, forming a spreading mat against barren ground that is about 6-18" across, but usually less than 1" tall. However, where other vegetation is present, the stems may ascend to 6" in height. The slender round stems are more or less covered with hairs, and often turn pale red in the presence of bright sunlight. The opposite leaves are up to ¾" long and ¼" across, but they are usually smaller in size. They are oblong in shape, smooth or slightly toothed along the margins, and have short petioles. Each leaf is more or less oblique at the base (i.e., asymmetrical where the petiole joins the leaf blade), and it often has a red blotch near the middle of the upper surface. Both the stems and the major veins of the leaves contain a milky juice. From the axils of the leaves, there often appears either a single flower or, more commonly, a small leafy cluster of flowers. Like other Chamaesyce spp. (Ground Spurges), Prostrate Spurge is usually monoecious, each plant having separate male and female flowers. Less commonly, a plant may be unisexual, producing either all male flower or all female flowers, but not both. Each male or female flower is less than 1/8" across, and consists of a small floral bract in the shape of a cup, which contains 4 glands with petal-like extensions along its upper edge. These petal-like structures are either white or light red and quite small. Each cup-shaped bract has a slit on one side that is 1/41/3 as long as the bract. Each female flower has a 3-valved seed capsule that is hairy and hangs along the side of the bract from a stout pedicel. Each valve of the capsule contains a single 4-angled seed that is minutely pitted and has faint transverse ridges across its surface. The seeds are hydrophilic and can adhere to surfaces when they are wet. Each male flower has 4 stamens with yellow anthers that extend beyond the rim of the cup-shaped bract. Neither female nor male flowers have any petals or sepals. The blooming period occurs from mid-summer through the fall and lasts about 2 months for individual plants. There is no noticeable floral scent. The root system consists of a slender taproot. This plant spreads by reseeding itself.