Flora of North America species comparison

usually single, occasionally 2–several, 4-angled with wings 0.1–0.5 mm wide, 1.5–5(–7.5) dm, branching all opposite or secondary and/or tertiary occasionally alternate.

4-angled with wings to 0.2 mm wide, branching alternate or proximal rarely opposite.

basal and cauline or only cauline present at flowering time;

basal blades spatulate-obovate;

cauline blades linear-oblong to ovate-lanceolate, 0.8–2.5(–6) cm × 3–8(–18) mm.

all cauline at flowering time;

blade linear to narrowly lanceolate, 0.7–3 cm × 1–4.5(–6) mm.

cymes of compact cymules;

pedicels 1–2(–4) mm.

open cymes;

pedicels (2–)10–40 mm.

5-merous;

calyx tube widely obconic to campanulate, 1.5–3(–3.5) mm, mid- and commissural veins about equally prominent, low-ridged, lobes linear-subulate or rarely wider, 2–8(–11) mm;

corolla white throughout (sometimes drying yellow or salmon) or occasionally with a yellow eye, projections of eye into corolla lobes, when present, triangular, without a contrasting border, tube 2.5–7 mm, lobes oblanceolate to narrowly spatulate-obovate, 4.5–15 × 1.5–6 mm, apex rounded to obtuse;

anthers coiling circinately.

5-merous;

calyx tube campanulate, 2.8–5.5 mm, commissural veins more prominent than midveins, ridged, lobes linear, 9–13 mm;

corolla purplish pink or rarely white, eye yellow or yellowish green, projections of eye into corolla tube oblong to narrowly triangular, alternating with shorter white or paler yellow zones, tube 3–7 mm, lobes narrowly spatulate-obovate, 8–18 × 3–6 mm, apex rounded;

anthers coiling circinately.

 = 32, 34.