Description

Key Characters:

Growth Form: Shrubs or herbs.

Stems:

Roots:

Leaves: Leaves simple. Opposite and decussate (pairs of leaves alternating 90 degrees between nodes). Blades usually with prominent cystoliths. Margins entire. Petiolate to subsessile. Stipules absent.

Flowers: Flowers in dense axillary or terminal spikes or racemes. each inflorescence subtended by bracteoles, these often large and spinose. Flowers bisexual (perfect). Calyx distinctly zygomorphic, deeply 4-lobed, 2 segments larger than the other 2, the pairs often also of different shapes. Corolla 5-lobed, the lobes broadly spreading and subequal. 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; ovule placentation axile; style filiform, simple.

Fruit: Capsules with two cells; usually dehiscing explosively; capsules flattened perpendicular to line of dehiscence. Seeds 4; on small hooked stalks (modified funiculus) that ejects the seeds from the capsule; embryos usually large; endosperm absent.

Ploidy:

Habitat: Often xerophytic; tropical areas.

Elevation Range: