Description

Key Characters:

Growth Form: Erect or decumbent annual herbs.

Stems: Stems slender, erect or decumbent, 15–45(–80) cm long, unbranched or branched from base.

Roots: Fibrous root system.

Leaves: Leaves simple. Alternate. Blades broadly elliptic to ovate, 6–30 mm long, 3–12 mm wide. Apex rounded, obtuse, or acute, sometimes acuminate. Base clasping cordate, obtuse, broadly cuneate, or rounded. Surfaces glabrous or hispid on the veins and margins. Margins crenate. Short-petiolate and obtuse below, sessile and acute above. Stipules absent.

Flowers: Flowers 1–3 in axil, sessile; earlier flowers rudimentary; actinomorphic or, if zygomorphic, then often laterally fenestrate or dorsally cleft, connate, with 5 valvate lobes. Flowers bisexual (perfect) or rarely unisexual, sessile; nearly all cleistogamous, only the single terminal flower regularly chasmogamous. Hypanthium campanulate, oblong, or obconic. Calyx lobes triangular to ovate, 4–7 mm long in chasmogamous flowers, 3–5 mm long in cleistogamous flowers, glabrous or sparsely pubescent. Corolla bluish purple or rose-purple, rarely white, rotate, tube 1–1.5 mm long, the lobes oblong, 5–9 mm long, ciliate at tips and sparsely pubescent on the veins. Stamens free, 5, alternate with corolla lobes; anthers elongate, longer than filaments, dithecal, opening by longitudinal slits, coherent but separating after anthesis or connate and forming a tube into which pollen is shed; filaments distinct or connate above, attached to the epigynous nectary disk or to base of corolla, rarely adnate to corolla tube. Ovary inferior, sometimes only partly so, rarely almost superior; ovules numerous, placentation axile; stigmas densely puberulent, wet or dry, 2–5-lobed, appressed and nonreceptive as the style grows through the anther tube, pushing out the pollen, after which the stigmas spread apart and become receptive; style upright, divided at the tip into 3 short branches, reduced in cleistogamous flowers.

Fruit: Poricidal capsule; ellipsoid; clavate; or ovoid; 4–7 mm Iong; 1.3–1.7 mm wide; glabrous or sparsely pubescent; with 3 distal pores. Seeds chestnut brown; lenticular; smooth; shiny; 0.5–0.7 mm long; with a straight; short to spatulate dicotyledonous embryo embeded in oily endosperm.

Ploidy: 2n = 56

Habitat: Sparingly naturalized in dry; disturbed sites.

Elevation Range: