This annual plant is 4-16" tall, usually forming a tuft of leafy stems that are ascending to sprawling. These stems are branched at the base near the crown of the plant, otherwise they are unbranched. Individual stems are light green, terete, and glandular-hairy. Pairs of opposite leaves occur along these stems (typically at intervals of 1-2½"). These leaves are ¾-2" long, 5-9 mm. across, and elliptic, oblong-lanceolate, or oblong-oblanceolate in shape. The leaf margins are smooth (entire) and slightly ciliate. The leaf surfaces are medium green and either sparsely short-pubescent or hairless. Each leaf has a prominent central vein. The upper stems terminate in either cymes or compound cymes of flowers (usually the latter); these cymes are dichotomously branched and variable in size. Each terminal branch of the inflorescence typically has 3 flowers with divergent slender pedicels up to 1¼" long. While the flower buds are nodding, the flowers are more erect. Similar to the stems, the branches and pedicels of each inflorescence are light green, terete, and glandular-pubescent. At the base of each pair of branches in an inflorescence, there is a pair of leafy bracts up to ¾" and 5 mm. across. These bracts are lanceolate in shape and they lack membranous margins. The flowers are up to ¼" across while they are in bloom. Each flower has 5 white petals with notched tips, 5 green sepals, an ovary with 5 styles, and 10 stamens (usually). The sepals are lanceolate in shape with membranous margins and short-pubescent; they are about 3-5 mm. long. The petals are the same length or a little longer than the sepals. The blooming period occurs from mid-spring to early summer, lasting about 1 month. Usually, only a few flowers are in bloom at the same time. Sometimes cleistogamous flowers that fail to open are produced. Afterwards, the flowers are replaced by cylindrical seed capsules that become 8-12 mm. long at maturity. Like the flowerbuds, they tend to nod downward. Mature seed capsules are membranous, light tan, longitudinally veined, and often slightly curved; they are more than twice as long as the sepals. Each seed capsule has an open rim at its apex with 10 tiny teeth. Each seed capsule contains several tiny seeds about 0.5 mm. in length. The seeds are obovoid, somewhat flattened, brownish, and minutely tuberculate (warty). The root system system consists of a shallow spreading taproot.