Flora of North America species comparison

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

(from short rhizomes, green) single, branched distally, puberulent throughout.

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 (± vertical); petiolate (petioles 10–30 mm);

blades ± 3-nerved distal to bases, deltate to rhombic, 25–80 × 20–60 mm, bases broadly cuneate, margins usually serrate (teeth uneven), sometimes crenate, apices acute, faces glabrate to sparsely puberulent, gland-dotted.

5;

corollas 3–3.5 mm.

5;

corollas 3.5–4 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.

8–12 in 2–3 series, elliptic to oblong, 1.5–5 × 0.8–1 mm, apices acute to acuminate, abaxial faces puberulent, gland-dotted.

in corymbiform arrays.

in corymbiform arrays.

2–3 mm;

pappi of 30–40 bristles 3.5–4 mm.

1.2–1.5 mm;

pappi of 20–35 bristles 3.5–4.5 mm.

= 20, 30, 40.

= 20.