Flora of North America species comparison

erect (round to 4-angled or -ribbed), unbranched or sparingly branched (from proximal nodes, puberulent and/or villous to pilose, often in lines, sometimes glabrate).

mostly cauline; usually opposite (proximal often withering before flowering, distal sometimes alternate);

petiolate;

blades (proximal) 3–5-nerved, triangular to broadly ovate (bases obtuse to cordate), margins subentire to dentate, faces glabrous or sparsely villous (at least along veins and on margins), not gland-dotted.

cylindric, [2–]3–4+ mm diam.

flat, epaleate.

8–12;

corollas greenish white to cream-colored, (bases slightly enlarged, tubes and throats not markedly differentiated externally) throats cylindric to filiform, lobes 5, triangular-ovate (very short);

styles: bases not enlarged, glabrous, branches ± filiform (appendages linear or weakly clavate).

persistent (spreading in age), (12–)17–22+ in 3–4+ series, 3-nerved, lance-deltate or lanceolate to linear, unequal (apices acute to acuminate).

discoid, in spiciform or narrow, ± paniculiform arrays (subtended by lanceolate to linear, scalelike bracts).

± prismatic (usually 5-angled) or subcylindric, usually 5-ribbed, minutely puberulent;

pappi usually readily falling, of 8–13 plumose bristles or setiform scales in 1 series (basally coherent or weakly connate, falling together or in groups).

= 10.