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.

1–several, clustered, proximally terete, distally sometimes ± 4-angled but not winged, 2.5–10.5 dm, branching opposite throughout.

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-lanceolate to narrowly or occasionally widely elliptic-ovate, 1–4(–6) cm × 3–14(–22) mm.

cymes of compact cymules;

pedicels 1–2(–4) mm.

corymboid dichasia of compact cymules;

pedicels 1–8(–15) 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(or 6)-merous;

calyx tube shallowly campanulate, 1–2(–3) mm, midveins somewhat more prominent than commissural veins, low-ridged, commissural veins scarcely ridged, lobes narrowly lanceolate to filiform, (2–)4–9(–14) mm;

corolla white throughout (sometimes drying cream to yellow), tube 2.5–6 mm, lobes oblanceolate, (5–)7–21 × 2.5–8 mm, apex rounded;

anthers recurving.

 = 32, 34.

 = 36.