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stemless ironweed

ironplant, plains ironweed

Habit Plants 4–6(–10) dm. Plants 3–5(–8+) dm.
Stems

± puberulent, glabrescent.

puberulent, 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 narrowly lanceolate to lance-linear, 5–15+ cm × (2.5–)8–12+ mm, l/w = 8–20(–30+), abaxially glabrate (pitted, awl-shaped hairs in pits), adaxially puberulent, glabrescent (sometimes pitted).

Peduncles

5–50 mm.

(3–)10–35 mm.

Involucres

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

narrowly campanulate, (7–)9–11 × 5–6 mm.

Florets

30–40(–55+).

10–25+.

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.

35–40+ in 5–6+ series, glabrescent, margins arachno-ciliolate, the outer lance-ovate, 1–2 mm, inner oblong to linear-oblong, 6–9+ mm, tips ± acuminate.

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.

4–5 mm;

pappi stramineous to purplish, outer subulate scales or bristles 30+, 0.6–2+ mm, intergrading with 40+, 8–9+ mm inner subulate scales or bristles.

2n

= 34.

= 34.

Vernonia acaulis

Vernonia marginata

Phenology Flowering Jul–Aug. Flowering Jul–Aug.
Habitat Open woods, pine savannas, bogs, disturbed places Ditches, sandy flats, stream banks
Elevation 10–300 m (0–1000 ft) 600–2000 m (2000–6600 ft)
Distribution
from FNA
FL; GA; NC; SC
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; KS; NM; OK; TX; Mexico (Coahuila)
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 19, p. 208. FNA vol. 19, p. 211.
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. arkansana, V. baldwinii, V. blodgettii, V. fasciculata, V. flaccidifolia, V. gigantea, V. glauca, V. larseniae, V. lettermannii, V. lindheimeri, V. missurica, V. noveboracensis, V. pulchella, V. texana
Synonyms Chrysocoma acaulis V. altissima var. marginata
Name authority (Walter) Gleason: Bull. New York Bot. Gard. 4: 222. (1906) (Torrey) Rafinesque: Atlantic J. 1: 146. (1832)
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