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stemless ironweed

Larsen's ironweed

Habit Plants 4–6(–10) dm. Plants 7–10+ dm.
Stems

± puberulent, glabrescent.

tomentose to pannose.

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 linear, 5–9(–12+) cm × 3–5(–8+) mm, l/w = 16–32, abaxially tomentose, adaxially densely sericeo-tomentose.

Peduncles

5–50 mm.

10–60 mm.

Involucres

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

± hemispheric, 8–12 × 7–12 mm.

Florets

30–40(–55+).

40–50+.

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+ in 5–6+ series, sericeo-tomentose to pannose, including margins, the outer lance-deltate, 1–3 mm, the inner lanceolate, 7–11+ mm, tips acute.

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.

3.5–4+ mm;

pappi stramineous, outer subulate scales or bristles 20+, 0.6–1.5+ mm, intergrading with 30+, 6–7+ mm inner subulate scales or bristles.

2n

= 34.

= 34.

Vernonia acaulis

Vernonia larseniae

Phenology Flowering Jul–Aug. Flowering Jun.
Habitat Open woods, pine savannas, bogs, disturbed places Arroyos, on limestone
Elevation 10–300 m (0–1000 ft) 800–900 m (2600–3000 ft)
Distribution
from FNA
FL; GA; NC; SC
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; Mexico (Coahuila)
Source FNA vol. 19, p. 208. FNA vol. 19, p. 210.
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. lettermannii, V. lindheimeri, V. marginata, V. missurica, V. noveboracensis, V. pulchella, V. texana
Synonyms Chrysocoma acaulis V. lindheimeri var. leucophylla
Name authority (Walter) Gleason: Bull. New York Bot. Gard. 4: 222. (1906) B. L. King & S. B. Jones: Brittonia 27: 84. (1975)
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