Description

Key Characters:

Growth Form: Malodorous annual herbs.

Stems: Stems erect or ascending, 1–4 dm long, usually many-branched, sometimes side branches short, pubescent with multicellular hairs.

Roots:

Leaves: Leaves simple. Alternate. Blades ovate, (0.5–)1–4.5 cm long, 0.6–2 cm wide. Surfaces glandular-dotted with yellow glands, also usually sparsely pubescent with multicellular hairs. Margins coarsely toothed. Petioles pubescent. Stipules absent.

Flowers: Flowers in axillary glomerules, sometimes grouped into leafy, interrupted spikes toward the tips of the branches. Flowers bisexual (perfect), small. Calyx (3–)5-lobed, persistent, 0.6–0.8 mm long, enclosing the fruit at maturity, each lobe with a hooded wing or keel on back, the wing or keel entire or sometimes slightly toothed toward apex, pubescent with multicellular and sometimes also gland-tipped hairs. Corolla (petals) absent. Stamens 1–5; anthers dithecal, opening by longitudinal slits. Ovary superior, 2–3(–5)-carpellate, 1-celled, placentation basal; ovule 1; stigmas dry; styles 2–5.

Fruit: Utricles. Seeds 1 per fruit; dark brown; vertical; 0.5–0.7 mm in diameter; margins distinct; acute.

Ploidy: 2n = 16

Habitat: Dry; disturbed sites.

Elevation Range: 0–1,200 m.