Description

Key Characters:

Growth Form: Matted, pubescent, short-lived perennial herb.

Stems: Stems often swollen at the nodes. depressed, basal, lateral shoots, stems 3–7 dm long, hirsute to sometimes glandular.

Roots:

Leaves: Leaves simple. Opposite. Blades oblanceolate to oblong or elliptic–ovate, 10–25 mm long, 3–10 mm wide. Base leaf bases often connate around the stem. Surfaces conspicuously hirsute. Margins entire. Sessile. Stipules absent.

Flowers: Flowers in terminal, rather compact, dichotomous cymes, but in fruit becoming more open. Flowers bisexual (perfect) or unisexual (and then plants usually dioecious), actinomorphic. Calyx of 4(5) sepals; sepals, distinct, nearly distinct, or connate into a conspicuous tube; 3–6.5 mm long, hirsute, margins scarious. Petals as many as sepals, 2–cleft; white, 4–5 mm long; notched, cleft, or sometimes fibriate or divided, sometimes sharply differentiated into an expanded part and a basal claw, then often with 2 small outgrowths present at the juncture of the limb and claw. Stamens 5–10, rarely fewer, distinct or adnate to petals at base to form a short tube, which may be adnate to the gynophore or sometimes adnate to lower part of calyx, petaloid staminodes sometimes present; anthers dithecal, opening by longitudinal slits. Ovary superior.

Fruit: Capsules cylindrical; curved; 9–12 mm long; dehiscent at apex by twice as many teeth as styles. Seeds numerous; reddish brown 0.4–0.8 mm long; tuberculate; globose or reniform; perisperm starchy; hard or rarely soft; true endosperm absent.

Ploidy: 2n = 126; 136–152; 160

Habitat: Naturalized in usually wet to sometimes dry; disturbed habitats.

Elevation Range: 0–3,900 m.