Flora of North America species comparison

single, terete, 1.5–7 dm, branching all or mostly alternate.

single, terete or slightly 4-ridged but not angled or winged, 1.5–5(–6.5) dm, branching opposite or alternate.

all cauline or basal occasionally persistent at flowering time;

blade linear to oblong-lanceolate, 0.5–3 cm × 1–5(–7) mm.

cauline and often also basal present at flowering time;

basal blades widely oblong-spatulate;

cauline blades abruptly differentiated, linear, 1–10 cm × 1–3 mm.

open cymes or solitary flowers at ends of branches;

pedicels (10–)20–40(–50) mm.

flowers solitary or in dense, few-flowered clusters, sessile.

5-merous;

calyx tube obconic, 1–3 mm, mid- and commissural veins about equally prominent, not or low-ridged, lobes filiform, 3–8 mm;

corolla white, eye greenish yellow, projections of eye into corolla lobes without a contrasting border, tube 1–3 mm, lobes oblanceolate, 6–18 × 2–7 mm, apex obtuse to acute;

anthers coiling circinately.

7–12-merous;

calyx tube widely campanulate, 3–8 mm, not ridged, lobes setaceous, 3–17 mm;

corolla pink, eye greenish yellow, projections of eye into corolla tube oblong, without a border, tube 6–10 mm, lobes oblanceolate to narrowly spatulate-obovate, 12–30 × 4–11 mm, apex rounded to obtuse;

anthers slightly twisting helically, not coiling circinately.

 = 32.

 = 28.