Description

Key Characters:

Growth Form: Annual herbs.

Stems: Stems decumbent, 0.2-4 dm long, usually many-branched, sparsely to densely crisped puberulent in lines on the angles.

Roots:

Leaves: Leaves simple. Opposite. Blades elliptic to elliptic-lanceolate, 0.4-3.5 cm long, 0.2-1.6 cm wide. Apex acute to rounded. Base cuneate. Scabridulous near margins and usually crisped puberulent along principal veins on lower surface. Margins with 1 to numerous filiform setae. Petioles 0-5 mm long. Stipules adnate to petioles, forming a sheath, ca. 2 mm long, with ca. 7 setae 1-3 mm long.

Flowers: Flowers few in axillary, dense, sessile clusters, subtended by 1-2 or more pairs of bract-like leaves, stipule-derived bracteoles with setae 1.8-2 mm long; hypanthium ca. 0.5 mm long. Flowers usually small, bisexual (perfect), sessile, insect-pollinated, often heterostylous. Calyx lobes 2(-4), 0.6-0.8 mm long with open aestivation, ciliate, usually deltate, oblong, or lanceolate, usually persistent, sometimes with intermediate teeth. Corolla funnelform or salverform, white, 0.6-0.7 mm long, the tube usually very slender, the lobes (3)4, spreading, valvate in bud; nectary disk usually present. Stamens 4, alternate with the corolla lobes, inserted on corolla tube or throat, usually exserted; anthers dithecal, opening by longitudinal slits. Ovary inferior, occasionally partly so, or very rarely superior, 2-celled; ovules 1 per cell, attached to middle of septum; style many as carpels, terminal, slender, filiform, exserted; stigmas lobed or capitate, dry or occasionally wet.

Fruit: Fruit oblong; compressed; ca. 1 mm long; finely transversely wrinkled; puberulent; dehiscent. Seeds 2; chestnut brown or yellowish brown; oblong-ellipsoid; 0.7-1 mm long; minutely reticulate; the areolae transversely wider than high; with well-developed oily endosperm; or endosperm occasionally scanty or absent.

Ploidy:

Habitat: Recently naturalized in relatively dry areas.

Elevation Range: