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Arkansas ironweed, great ironweed

New York ironweed

Habit Plants 8–12(–20) dm. Plants 8–12(–20) dm.
Stems

scabrellous to pilosulous, glabrescent.

puberulent, glabrescent.

Leaves

mostly cauline;

blades lance-linear, 6–14(–20) cm × 7–15(–25) mm, l/w = 7–10(–18), abaxially scabrellous (hairs awl-shaped), resin-gland-dotted, adaxially scaberulous, glabrescent, resin-gland-dotted.

mostly cauline;

blades ± lanceolate, 9–15(–25+) cm × 15–45(–60+) mm, l/w = (3.3–)4–6+, abaxially scabrellous, tomentose, or pannose, resin-gland-dotted, adaxially scabrellous, often resin-gland-dotted.

Peduncles

2–5 cm.

2–35 mm.

Involucres

± hemispheric, 11–15 × 11–15 mm.

± hemispheric, 6–10 × 7–10 mm.

Florets

50–100+.

30–45(–65).

Phyllaries

(50–)60–70+ in 5–6 series, scabrellous (and resin-gland-dotted), margins ciliolate, the outer lance-ovate, 3–8+ mm, inner lanceolate, 12–15 mm, tips subulate to filiform.

35–60+ in 4–6+ series, sparsely tomentulose, glabrescent, margins ciliolate, the outer lanceolate to subulate, 1–3 mm, inner oblong, 7–9+ mm, tips subulate to filiform.

Heads

in ± corymbiform arrays.

in corymbiform to paniculiform arrays.

Cypselae

3–5 mm;

pappi fuscous to purplish, outer scales 25–30+, 0.5–1 mm, contrasting with 25–30+, 5–7 mm inner bristles.

3.5–4+ mm;

pappi fuscous to purplish, outer scales 20, 0.2–0.6+ mm, contrasting with 30–40+, 5–7+ mm inner bristles.

2n

= 34.

= 34.

Vernonia arkansana

Vernonia noveboracensis

Phenology Flowering Aug–Oct. Flowering Aug–Oct.
Habitat Leas, roadsides, stream banks, in sand or on limestone Abandoned fields, marshes, roadsides
Elevation 200–300 m (700–1000 ft) 10–600 m (0–2000 ft)
Distribution
from FNA
AR; KS; MO; OK
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; CT; DC; DE; FL; GA; MA; MD; NC; NJ; NY; PA; RI; SC; TN; VA; WV
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Discussion

Vernonia arkansana was published in April, V. crinita in October 1838.

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

Source FNA vol. 19, p. 208. FNA vol. 19, p. 209.
Parent taxa Asteraceae > tribe Vernonieae > Vernonia Asteraceae > tribe Vernonieae > Vernonia
Sibling taxa
V. acaulis, V. angustifolia, V. baldwinii, V. blodgettii, V. fasciculata, V. flaccidifolia, V. gigantea, V. glauca, V. larseniae, V. lettermannii, V. lindheimeri, V. marginata, V. missurica, V. noveboracensis, V. pulchella, V. texana
V. acaulis, V. angustifolia, V. arkansana, V. baldwinii, V. blodgettii, V. fasciculata, V. flaccidifolia, V. gigantea, V. glauca, V. larseniae, V. lettermannii, V. lindheimeri, V. marginata, V. missurica, V. pulchella, V. texana
Synonyms V. crinita Serratula noveboracensis, V. harperi, V. noveboracensis var. tomentosa
Name authority de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 264. (1838) (Linnaeus) Michaux: Fl. Bor.-Amer. 2: 95. (1803)
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