Citation: L., Sp. Pl. 831 (1753).

Derivation: Latin bis, twice; dens, tooth; referring to the two sharp awns of the pappus.

Synonymy: Not Applicable

Common name: None

Description:
Annual and perennial herbs; leaves cauline, flat, sessile or petiolate, simple or compound.

Capitula on long peduncles, terminal, in loose cymes or solitary, heterogamous, radiate or the rays absent; involucres campanulate, becoming reflexed in fruit, 2-seriate; outer bracts herbaceous, inner ones with membranous margins; receptacle convex, pitted, with narrow deciduous scales; ray florets uniseriate, sterile, ligulate, few or absent; disk florets numerous, bisexual, fertile, tubular, pentamerous; corolla funnel-shaped; anthers obtuse to slightly sagittate at the base, with a deltoid appendage at the apex; style branches linear, with narrow acute terminal appendages, with hairs on the outer faces.

Achenes linear, compressed; pappus of awns. (E. E. Sherff (1937) Field Mus. Nat. Hist. Botl Ser. 16:1-709.)

Distribution:  About 230 species in tropical and warm temperate regions.

Biology: No text

Author: Not yet available