Flora of North America species comparison

(from short caudices or stout rhizomes) single, sparsely branched distally, pubescent throughout (nodes sometimes with galls).

(from short caudices) single, branched distally, puberulent throughout (lateral buds often develop fertile and infertile branches).

usually opposite (nodes often appearing leafy, lateral buds producing 2+ pairs of leaves);

sessile or subsessile;

blades strongly 3-nerved from bases, lance-elliptic to oblanceolate, 50–120 × 5–20 mm, bases ± cuneate, margins entire proximally, serrate distally, apices acuminate, faces puberulent or villous, gland-dotted.

opposite (proximal) or alternate (lateral buds dormant or producing 1 pair of leaves);

sessile;

blades (often pinnately or ternately lobed) or lobes pinnately nerved, linear, 20–80 × 0.5–2.5(–4) mm, bases cuneate, margins entire, apices acuminate, faces puberulent, gland-dotted.

5;

corollas 3–3.5 mm.

5;

corollas (sometimes with purple throats) 2.5–3 mm.

8–10 in 2–3 series, oblong, 1–4 × 0.5–1.5 mm, (bases tapered) apices rounded to acute (not mucronate), abaxial faces pubescent throughout.

7–10 in 2–3 series, (sometimes purple) elliptic to oblong, 1–3 × 0.5–0.8 mm, (margins hyaline) apices acuminate and mucronate, abaxial faces puberulent (mostly on midveins), usually gland-dotted.

in corymbiform arrays.

in paniculiform arrays.

2–3 mm;

pappi of 30–40 bristles 3.5–4 mm.

1–1.7 mm;

pappi of 20–30 bristles 3–3.5 mm.

= 20, 30, 40.

= 20.