Flora of North America species comparison

usually 1, erect or prostrate to decumbent or ascending (sometimes rooting at nodes), usually branched, glabrous or ± strigillose to villous (hairs mostly basifixed).

usually mostly cauline [basal]; alternate [opposite];

petiolate or sessile;

blades obovate or spatulate to lanceolate or linear, sometimes 1–3-pinnately [palmati-pinnately] lobed, ultimate margins entire or irregularly toothed, faces glabrous or ± strigillose to villous [lanate] (hairs mostly basifixed).

broadly hemispheric to saucer-shaped, 3–12+[–15+] mm diam.

flat to convex [conic], epaleate (sometimes ± covered with persistent stalks of florets).

0 [5–8+, pistillate, fertile;

corollas white] (peripheral pistillate florets 8–80+ in 1–3+ series; corollas usually none).

12–200+[–600+], bisexual, fertile [functionally staminate];

corollas ochroleucous or yellow, tubes ± cylindric (bases sometimes adaxially saccate), throats abruptly ampliate, lobes (3–)4, ± deltate (sometimes one larger than others, usually each with central resin canal).

persistent, 13–30+ in 2–3+ series, margins and apices (colorless, light to dark brown, or purplish) scarious.

disciform [discoid or radiate], borne singly (peduncles sometimes dilated).

obovoid to oblong, ob-compressed or -flattened, ribs 2, lateral, sometimes becoming wings, faces ± papillate (pericarps relatively thin, sometimes with myxogenic cells and/or 2 lateral resin sacs);

pappi 0.

= 10.