Description

Key Characters:

Growth Form: Erect, slender annual herbs.

Stems: Stems often swollen at the nodes, 2–5 dm long unbranched or branched, internodes, usually densely glandular puberulent, restricted to middle part of stem, sometimes glabrate.

Roots:

Leaves: Leaves simple. Opposite or rarely alternate. Basal leaves linear–oblanceolate to narrowly oblanceolate, 20–40 mm long, 2–5 mm wide; cauline leaves linear–subulate, 13–40 mm long, 1–2 mm wide, sheath 3–7(–8) mm long. Base leaf bases often connate around the stem. Margins entire. Veins parallel. Petioles absent. Stipules absent.

Flowers: Flowers in clusters. Flowers bisexual (perfect), actinomorphic. Calyx 8–14 mm long; tubular, 5-toothed, distinctly 5–15–nerved or striate, commissures scarious; sepals distinct, nearly distinct, or connate into a conspicuous tub. Corolla of 5 petals, ± clawed, without coronal scales; pink to purplish, 11–16 mm long, the obcordate limb 2–3.5 mm wide; 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 10, 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 dehiscing at apex by 4 teeth. Seeds compressed; ca. 1.3 mm long; the surface papillose; perisperm starchy; hard or rarely soft; true endosperm absent.

Ploidy: 2n = 30

Habitat: Sparingly naturalized but locally common in open; dry; disturbed areas and pastures.

Elevation Range: 800–1550 m.