Flora of North America species comparison

(from short caudices) single, sparsely branched distally, puberulent throughout.

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

usually opposite (sometimes whorled);

sessile;

blades pinnately nerved, oblong (tapering toward apices), 50–150+ × 15–40 mm, bases connate-perfoliate, margins serrate, apices acute, faces pilose, gland-dotted (abaxial), glabrate, not gland-dotted (adaxial).

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.

7–11;

corollas 2.5–3 mm.

5–8;

corollas 2.5–3 mm.

7–10 in 1–2 series, oblong, 2–4.5 × 0.6–1 mm, apices (whitish) acute to acuminate, abaxial faces villous or 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 20–30 bristles 3–3.5 mm.

2–3 mm;

pappi of 30–40 bristles 3.5–4.5 mm.

= 20.

= 30, 40.