Bidens hyperborea

Annuals, (5–) 10–30 (–70+) cm. Leaves sessile or petioles 5–25 mm (± winged); blades oblanceolate to linear, 15–40 (–100+) × (3–) 6–10 (–15+) mm, bases cuneate, margins entire or ± serrate, sometimes ciliate, apices rounded or obtuse to attenuate, faces glabrous. Heads borne singly or in 2s or 3s. Peduncles 10–60 mm. Calyculi of 2–3 (–9) erect, oblanceolate to lance-linear (± foliaceous) bractlets or bracts (6–) 10–20 (–75+) mm, margins usually ciliolate, abaxial faces glabrous. Involucres usually ± campanulate to cylindric, sometimes ± hemispheric, 5–7 (–9) × (4–) 7–10 mm. Phyllaries 6–8 (–12), oblong, 6–11 mm (tips usually yellow, as tips of paleae). Ray-florets 0 or 3–7; laminae pale-yellow, 4–12 mm. Disc-florets 15–30 (–60); corollas yellow (often orange-tipped), 3–4 mm. Cypselae blackish to olive, flattened, narrowly cuneate, outer 4–9 mm, inner 5–10 mm, margins retrorsely barbed, apices ± truncate to convex, faces ± 1-nerved, ± striate, glabrous; pappi of (2–) 3–4 ± erect, retrorsely barbed awns 2–5 mm.

Phenology: Flowering Aug–Oct.
Habitat: Marshes, borders of estuaries
Elevation: 0–10 m

N.B., N.S., Nunavut, Ont., Que., Maine, Mass., N.H., N.Y.

Discussion

Selected References

None.

Lower Taxa