Isis (Oken) 1818(5): 822. 1818

Etymology: Greek heteros -, different, and anthemis, a genus name
Treatment appears in FNA Volume 19. Treatment on page 551. Mentioned on page 30, 487.

Annuals, 10–30(–100+) cm (plants sticky, viscid). Stems 1, erect, usually branched distally, hirtellous to pilosulous (hairs basifixed, some gland-tipped). Leaves mostly cauline; alternate; petiolate or sessile; blades obovate to oblong (bases sometimes ± clasping), often pinnately lobed, ultimate margins usually dentate, rarely entire, faces hirtellous to pilosulous (some hairs gland-tipped). Heads radiate, borne singly or in 2s or 3s. Involucres hemispheric or broader, 12–25+ mm diam. Phyllaries persistent, 20–30+ in 2–3+ series, distinct, ovate or obovate to lance-deltate or lanceolate (not keeled abaxially, usually each with central resin canal), unequal, margins and apices scarious (tips of inner usually dilated). Receptacles convex to conic, epaleate. Ray florets 13–21+, pistillate, fertile; corollas yellow, laminae ± linear. Disc florets 40–80(–100+), bisexual, fertile; corollas proximally ochroleucous, distally yellow, tubes cylindric (usually gland-dotted), throats funnelform, lobes 5, deltate. Cypselae dimorphic: outer 3-angled (each angle ± winged, wings ± spine-tipped); inner ± compressed (adaxial angles ± winged, wings ± spine-tipped); ribs 0, faces glabrous (peric)arps without myxogenic cells or resin sacs; embryo sac development tetrasporic; pappi 0. x = 9.


Introduced; Mediterranean Europe, n Africa, widely adventive elsewhere.


Species 1.

Selected References