Capitula narrow, ± cylindric, subcorymbosely arranged, heterogamous, discoid. Florets whitish; pistillate marginal, in 2-3 series, filiform, minutely 3-5-toothed; perfect florets fewer, tubular, 5-toothed. Anthers obtuse at base; style-arms of perfect florets elongate, truncate. Achenes ± cylindric, striate or ribbed. Pappus-hairs ∞, soft, very slender, very obscurely barbellate. Phyll. in 1 row, linear, acute, subequal; subtended by a calyculus of a few minute bracteoles. Receptacle ± flat, nude. Annual or biennial herbs, or sts with a short-lived woody crown. Genus of c. 20 spp. of N. and S. America, Java, New Guinea, Australia, Tasmania, N.Z. Of the N.Z. spp. 4 are endemic, 4 occur also in Australia and/or Tasmania. The synonymy is confused.

Annual or perennial herbs. Lvs simple, subentire to 1-pinnatifid, alternate. Capitula in panicles; involucral bracts in 1 row, with supplementary bracts subtending involucre. Receptacle ± flat; scales 0. Outer florets ♀, not ligulate, filiform; inner florets ☿. Achenes all similar, ± cylindric, with c. 10 prominent ribs, and short antrorse hairs between ribs; pappus simple, sometimes caducous.