Flora of North America species comparison

arachnose, loosely tomentose, or villous (hairs crisped, jointed), glabrescent.

floccose-tomentose to canescent, sometimes unevenly glabrescent.

single.

1–(2–5).

progressively reduced distally; ± petiolate;

blades elliptic, lanceolate, linear, oblanceolate, rounded-deltate, or suborbiculate, 6–25 × 1–6 cm, bases ± tapered or truncate to cordate, margins entire or ± dentate (distal leaves sessile, bractlike).

progressively reduced distally; petiolate;

blades oblong-ovate to oblanceolate, (5–)10–30 × 1.5–4(–6) cm, bases tapered, margins dentate (denticles, dark, callous; mid leaves similar, sessile, smaller; distal leaves bractlike).

usually ± 8 or ± 13, sometimes 0;

corolla laminae 6–15(–20) mm (usually yellow, ochroleucous to white in one variety).

(± 3) ± 5;

corolla laminae 5–8 mm.

usually ± 13 or ± 21, rarely ± 8, (4–)5–12(–15) mm, tips usually black, sometimes green.

(± 5) ± 8, 6–8 mm, tips black.

of 1–5+ linear to filiform bractlets (seldom more than 2 mm).

of 2–5 linear bractlets (lengths to 1/3 phyllaries).

6–20(–40+) in corymbiform arrays (peduncle of terminal head often shorter than others).

20–60+ in corymbiform or subpaniculiform arrays.

usually glabrous, sometimes hirtellous (mostly on angles).

glabrous.

= 40, 80.

= 40. (A report of 2n = 46 is presumably erroneous.)