Alkali Yellowtops

Flaveria campestris is distinguished by subglomerulate capitulescences with 5–6(–8) florets per head, subtended by 3 leafy bracts, keeled phyllaries, and linear-lanceolate leaves with serrate or spinulose-serrate margins, and its distribution. The prevalence of F. campestris fluctuates greatly from year to year, generally depending on the existence of wet, saline habitat.

Annuals, 18–70(–90) cm (delicate or robust, mostly glabrous). Stems usually erect (tufted-pubescent at nodes). Leaves sessile; blades linear-lanceolate to lanceolate, 30–90 × 6–22 mm, bases barely connate, margins strongly to weakly serrate or spinulose-serrate. Heads (10–)15–100+, in tight subglomerules in corymbiform arrays. Calyculi of 2 linear-lanceolate bractlets 1–3 mm. Involucres urceolate or oblong, 6–7 mm. Phyllaries 3, elliptic, obovate, or oblong-obovate. Ray florets 0 or 1; laminae yellow, ovate, 1.5–2.5 mm (apices notched). Disc florets 5–6(–8); corolla tubes 0.8–1.3 mm, throats funnelform, 1.2–1.7 mm. Cypselae oblanceolate, linear, or oblong, 2.8–3.6 mm (those of rays longer by ca. 0.2 mm); pappi 0. 2n = 36 (18).