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.

usually single, occasionally 2–several, terete or distally ± 4-angled but not winged, 0.8–5 dm, branching all or mostly alternate.

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 elliptic to widely spatulate, 1–6(–10) cm × 4–30 mm.

cymes of compact cymules;

pedicels 1–2(–4) mm.

open, few-flowered cymes;

pedicels (10–)30–60 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.

5–7-merous;

calyx tube shallowly campanulate, 1.5–5 mm, midveins slightly more prominent than commissural, veins not ridged or midveins with low, narrow ridges, lobes oblanceolate to spatulate or ± foliaceous, 8–25(–32) mm;

corolla pale pink proximally, distally white, or white throughout except for eye, eye yellow, projections of eye into corolla lobes triangular, without a contrasting border, tube 3–6 mm, lobes oblanceolate to narrowly spatulate-obovate, 6–15 × 2–6 mm, apex rounded to obtuse;

anthers becoming slightly recurved.

 = 32, 34.

 = 64.