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Arkansas ironweed, great ironweed

narrowleaf ironweed, slimleaf ironweed

Habit Plants 8–12(–20) dm. Plants (2–)5–6+ dm.
Stems

scabrellous to pilosulous, glabrescent.

glabrous or glabrate.

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 filiform, 5–9+ cm × 1–3+ mm, l/w = 25–50+, abaxially glabrate (pitted, awl-shaped hairs in pits), adaxially puberulent, glabrescent (sometimes pitted).

Peduncles

2–5 cm.

6–20+ mm.

Involucres

± hemispheric, 11–15 × 11–15 mm.

narrowly campanulate, 7–9(–10+) × 4–5+ mm.

Florets

50–100+.

10–12+.

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.

30–40+ in 5–6+ series, sparsely tomentose, glabrescent, margins arachno-ciliolate, the outer lanceolate to subulate, 1–3 mm, inner oblong to lanceolate, 5–7+ mm, tips acute.

Heads

in ± corymbiform arrays.

in corymbiform 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.

3–4 mm;

pappi fuscous to purplish, outer scales 25+, 0.1–0.5 mm, contrasting with 35+, 6–7+ mm inner bristles.

2n

= 34.

= 34.

Vernonia arkansana

Vernonia lettermannii

Phenology Flowering Aug–Oct. Flowering Jul–Aug.
Habitat Leas, roadsides, stream banks, in sand or on limestone Flood plains, terraces
Elevation 200–300 m (700–1000 ft) 100–200 m (300–700 ft)
Distribution
from FNA
AR; KS; MO; OK
[WildflowerSearch map]
[BONAP county map]
from FNA
AR; OK
[WildflowerSearch map]
[BONAP county map]
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. 211.
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. lindheimeri, V. marginata, V. missurica, V. noveboracensis, V. pulchella, V. texana
Synonyms V. crinita
Name authority de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 264. (1838) Engelmann ex A. Gray: Notes Compositae, 78. (1880)
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