Description

Key Characters:

Growth Form: Annual or rhizomatous perennial herbs with watery sap.

Stems: Stems with few to numerous stinging hairs.

Roots:

Leaves: Leaves simple. Opposite. Margins dentate, serrate, or incised. (3–)5–7-veined. Petiolate. Stipules prominent, lateral, distinct or connate and interpetiolar.

Flowers: Flowers in axillary, racemose, paniculate or loose clusters. Flowers unisexual (and the plants monoecious or rarely dioecious). Calyx of staminate flowers deeply 4-lobed, the lobes imbricate, hispid; pistillate Calyx 4-lobed, the lobes nearly distinct, unequal, the inner 2 longer, enclosing the achene, hispid. Corolla (petals) absent. Stamens in staminate flowers 4; filaments incurved in bud, elastically reflexed when pollen is shed; anthers dithecal, opening by longitudinal slits. Ovary superior (pistillate flowers), straight, psuedomonomerous, 1-celled; ovule 1, basal; style 1; stigma sessile or nearly so, capitate–penicillate. Staminate pistillode cup-like, ovary vestigial and sterile.

Fruit: Achenes ovoid to deltoid; compressed; enclosed by inner lobes of the membranous or rarely fleshy calyx. Seeds 1 per achene; erect; with scanty endosperm; cotyledons suborbicular; fleshy.

Ploidy:

Habitat:

Elevation Range: