Description

Key Characters:

Growth Form: Herbs or shrubs.

Stems: Stems not woody, 0.5‒2 m long.

Roots:

Leaves: Leaves simple. Opposite and decussate (pairs of leaves alternating 90 degrees between nodes). Blades with abundant cystoliths at maturity. Margins entire. Petiolate. Stipules absent.

Flowers: Flowers in 1-sided spikes or racemes. Flowers bisexual (perfect); each subtended by 2 small bracts and 2 bracteoles of about equal size. Calyx 5-lobed, the lobes linear to lanceolate. Corolla 5-lobed, zygomorphic, white, blue, purple, rose, or yellow, funnelform. Stamens 4, in pairs, inserted on the corolla alternate with the lobes, sometimes 1 or more reduced to staminodes; anthers dithecal, opening by longitudinal slits. Ovary superior, 2-carpellate, placentation axile; pubescent; ovules 4; style filiform, simple; stigma 2-lobed or capitate.

Fruit: Capsules with two cells; usually dehiscing explosively; capsules ellipsoid to clavate. Seeds 2–4; orbicular; compressed; On small hooked stalks (modified funiculus) that ejects the seeds from the capsule; embryos usually large; endosperm absent.

Ploidy:

Habitat:

Elevation Range: