Flora of North America species comparison

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

(from short rhizomes) single, branched distally, densely pilose.

usually opposite (distal sometimes alternate, lateral buds dormant or producing 1 pair of leaves); simple, sessile or subsessile;

blades ± 3-nerved distal to bases, elliptic to lance-elliptic, (30–)50–70 × 5–25 mm (lengths mostly 2–5 times widths), bases narrowly cuneate, margins usually serrate, apices acute, faces puberulent or villous, densely gland-dotted.

usually opposite (distal sometimes alternate);

sessile;

blades ± 3-nerved or pinnately nerved, ovate, 3–9.8 × 1.6–5.7 cm, bases clasping or narrowly perfoliate, margins serrate, apices acute, faces (rugose) sparsely pilose (adaxial) or densely pilose (abaxial) and densely gland-dotted.

5;

corollas 2.5–3 mm.

5–8;

corollas 2.5–3 mm.

7–10 in 2–3 series, elliptic, 1–3 × 0.5–1 mm, apices rounded to acute (not mucronate), abaxial faces puberulent, gland-dotted.

7–10 in 2–3 series, 4–12 × 1–4 mm, apices (usually white) acuminate to acute, abaxial faces pilose, gland-dotted.

in corymbiform arrays.

in corymbiform arrays.

1.5–2 mm;

pappi of 30–40 bristles 2.5–3 mm.

2–3 mm;

pappi of 30–40 bristles 3.5–4.5 mm.

= 20.

= 30, 40.