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stemless ironweed

Arkansas ironweed, great ironweed

Habit Plants 4–6(–10) dm. Plants 8–12(–20) dm.
Stems

± puberulent, glabrescent.

scabrellous to pilosulous, glabrescent.

Leaves

mostly basal;

blades oblong-elliptic to spatulate (basal, the distal narrower), 11–25(–30) cm × (21–)60–75+ mm, l/w = 2–4(–5+), abaxially usually glabrous or glabrate, sometimes hirsutulous on veins, usually resin-gland-dotted, adaxially ± scabrellous or glabrate.

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.

Peduncles

5–50 mm.

2–5 cm.

Involucres

campanulate to hemispheric, 5–10 × 6–7 mm.

± hemispheric, 11–15 × 11–15 mm.

Florets

30–40(–55+).

50–100+.

Phyllaries

40–60 in 5–6 series, glabrate, margins ciliolate, the outer lance-linear, 2–4 mm, inner lance-ovate to lance-subulate, 5–9 mm, tips subulate to filiform.

(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.

Heads

in loose, corymbiform arrays.

in ± corymbiform arrays.

Cypselae

2.5–3+ mm;

pappi whitish to stramineous, outer scales ca. 20, 0.6–1 mm, contrasting with 25–40, 5–7+ mm inner bristles.

3–5 mm;

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

2n

= 34.

= 34.

Vernonia acaulis

Vernonia arkansana

Phenology Flowering Jul–Aug. Flowering Aug–Oct.
Habitat Open woods, pine savannas, bogs, disturbed places Leas, roadsides, stream banks, in sand or on limestone
Elevation 10–300 m (0–1000 ft) 200–300 m (700–1000 ft)
Distribution
from FNA
FL; GA; NC; SC
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[BONAP county map]
from FNA
AR; KS; MO; OK
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[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. 208.
Parent taxa Asteraceae > tribe Vernonieae > Vernonia Asteraceae > tribe Vernonieae > Vernonia
Sibling taxa
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. noveboracensis, V. pulchella, V. texana
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
Synonyms Chrysocoma acaulis V. crinita
Name authority (Walter) Gleason: Bull. New York Bot. Gard. 4: 222. (1906) de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 7: 264. (1838)
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