Description

Key Characters:

Growth Form: Low or slender, usually erect perennial or biennial herbs.

Stems: Caulescent, stems branched, glabrous.

Roots: From fusiform or tuberous roots or rootstocks.

Leaves: Leaves simple. Usually basal or alternate. Margins entire to deeply palmately or pinnately divided to decompound. Petioles sheathing. Stipules absent.

Flowers: Flowers in capitate inflorescences, usually numerous in cymes or racemes, the heads or compact umbels polygamous or staminate only. Involucre of entire to lobed bracts longer or shorter than the heads. Flowers unisexual; Perfect flowers sessile or stipitate; staminate flowers often pedicellate, without subtending bractlets. Calyx teeth prominent, persistent, sometimes connate. Corolla of 5 petals; petals usually yellow, purple, or greenish white, ovate to spatulate, with a narrower inflexed apex. Stamens 5, inserted on an epigynous disk. Ovary inferior, 2-celled; ovules 1 per cells, anatropous; styles 2, usually swollen at base into a stylopodium. Styles longer or shorter than the calyx teeth, the stylopodium depressed or absent; carpophore absent.

Fruit: Fruit oblong–ovoid to globose; slightly compressed laterally; mericarps subterete; densely covered with prickles; squamae; or tubercles; ribs absent; vittae evident or obscure; irregularly or regularly arranged. Seeds 1 per mericarp; embryo small; endosperm cartilaginous. seed face plane to sulcate.

Ploidy:

Habitat: Occurring in temperate regions of the world except Australia and New Zealand; but particularly abundant in the New World and eastern Asia.

Elevation Range: