Flora of North America species comparison

erect or ascending, glabrous or sparsely puberulent (in decurrent lines).

linear to narrowly elliptic, 10–50 × 1–5 mm, margins with 1–3 pairs of setae, faces glabrous or sparsely puberulent (dotted on margins with round oil-glands 0.2–0.7 mm).

mostly cauline, sometimes basal or basal and cauline; mostly opposite (distal sometimes alternate) or mostly alternate; petiolate or sessile;

blades usually elliptic, filiform, lanceolate, linear, or ovate, often 1(–2)-pinnately lobed, ultimate margins entire or toothed (often proximally bristly-ciliate), faces glabrous or puberulent to tomentose (usually bearing oil-glands, embedded pellucid glands filled with strong-scented, essential oils).

20–80 mm.

campanulate.

campanulate, cylindric, hemispheric, obconic, or turbinate.

flat or convex to hemispheric or conic, epaleate (receptacles sometimes pitted, pit margins sometimes fimbrillate to laciniate).

8(–13);

corollas 5–11 mm.

0 or 1–21+, pistillate, fertile;

corollas yellow to orange (sometimes with brown or mostly brown) or white to pink, magenta, or reddish purple.

(7–)20–55;

corollas 3.5–5 mm (2-lipped).

1–120+, usually bisexual and fertile [functionally staminate];

corollas yellow to orange or brown, or pinkish to purplish or reddish, tubes much shorter than to much longer than cylindric to funnelform throats, lobes 5, deltate to lance-linear (equal or unequal);

anther thecae pale or ± darkened;

stigmatic papillae in 2 lines.

distinct, oblong or narrowly obovate, 4–7 × 1–2 mm (dotted with 0–2, subterminal oil-glands plus 2–4 pairs of inconspicuous, round to narrowly elliptic, submarginal oil-glands).

falling or persistent, 3–21+ in 1–2 series (distinct or ± connate, mostly linear to lanceolate, usually subequal, usually some or all bearing pellucid oil-glands as in leaves).

0 or of 1–22 bractlets.

borne singly or in open, cymiform arrays.

radiate or discoid (sometimes radiant, e.g., in Thymophylla), usually borne singly, sometimes in loose to crowded, corymbiform or cymiform arrays.

3–4.5 mm, strigillose or short-pilose;

ray pappi of 1–4, antrorsely barbed awns 1–4 mm or coroniform;

disc pappi of 15–30, antrorsely barbed bristles 2.5–5 mm or coroniform.

mostly clavate to obpyramidal (lengths usually 2–3+ times diams.), glabrous or hairy;

pappi usually persistent, of 20–50 bristles in 1–2+ series, or of 5–20 (sometimes aristate) scales in 1–2 series, or combinations of bristles and scales in 1–2+ series, rarely coroniform or 0.

= 24 (as P. palmeri).