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crowned beggar-ticks, tall swamp marigold

Habit Annuals (biennials), (15–)30–50(–150+) cm.
Leaves

petioles 5–20+ mm;

blades ± deltate to ovate overall, 40–75(–150) × 10–45(–130) mm, usually laciniately 1–2-pinnatisect, ultimate lobes (3–)5–7+, oblanceolate or lanceolate to linear, (5–)10–30(–80+) × (1–)4–8(–12+) mm, bases cuneate, ultimate margins incised, dentate, serrate, or entire, little, if at all, ciliate, apices acute to attenuate, faces glabrous or ± hirtellous to strigillose.

Peduncles

20–150 mm.

Involucres

hemispheric or broader, 4–6(–8) × 6–12 mm.

Ray florets

(7–)8–9;

laminae golden yellow, 10–30 mm.

Disc florets

40–60(–80+);

corollas yellow, 3–5 mm.

Phyllaries

6–8(–10), oblong, 3–8 mm.

Calyculi

of (6–)8(–11), ascending to spreading, spatulate to linear, sometimes ± foliaceous bractlets or bracts 3–10(–18) mm, margins sometimes ciliate, abaxial faces glabrous.

Heads

usually in open, ± corymbiform arrays.

Cypselae

blackish or brown, flattened, narrowly cuneate, outer 3–6 mm, inner 5–9 mm (lengths mostly 2.5–4 times widths), margins antrorsely barbed or ciliate, apices ± truncate, faces obscurely 1-nerved, sometimes tuberculate, glabrous or sparsely hispidulous;

pappi of 2 erect, ± patently barbed awns or scales (0.4–)1–2.5(–4) mm.

2n

= 24.

Bidens trichosperma

Phenology Flowering Aug–Oct.
Habitat Marshes, estuaries
Elevation 0–300 m (0–1000 ft)
Distribution
from FNA
AL; AR; CT; DE; FL; GA; IA; IL; IN; KY; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NY; OH; PA; RI; SC; SD; TN; VA; WI; WV; ON; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Plants here called Bidens trichosperma have long been known as B. coronata (Linnaeus) Britton (or Britton ex Sherff). Alas, Britton’s B. coronata (1913) is a later homonym of B. coronata Fischer ex Colla (1834) and cannot be used.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21, p. 213.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Bidens
Sibling taxa
B. amplissima, B. aristosa, B. aurea, B. beckii, B. bidentoides, B. bigelovii, B. bipinnata, B. cernua, B. connata, B. discoidea, B. eatonii, B. frondosa, B. heterodoxa, B. heterosperma, B. hyperborea, B. laevis, B. lemmonii, B. leptocephala, B. mitis, B. pilosa, B. polylepis, B. tenuisecta, B. tripartita, B. vulgata
Synonyms Coreopsis trichosperma, B. coronata var. brachyodonta, B. coronata var. tenuiloba, B. coronata var. trichosperma
Name authority (Michaux) Britton: Bull. Torrey Bot. Club 20: 281. (1893)
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