Eupatorium rotundifolium |
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round-leaf boneset, round-leaf thoroughwort, roundleaf eupatorium |
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Habit | Perennials, 40–100+ cm. | ||||||||
Stems | (from short rhizomes) single, sparsely branched distally, puberulent. |
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Leaves | usually opposite (distal sometimes alternate, lateral buds dormant or producing 1 pair of leaves); sessile or subsessile; blades ± 3-nerved, usually ± deltate to orbiculate, sometimes ovate, 15–50(–70) × 15–40(–60) mm (lengths mostly 1–2 times widths), bases broadly rounded to truncate, margins crenate to serrate, apices acute, faces puberulent to villous, gland-dotted. |
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Florets | 5; corollas 3–4 mm. |
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Phyllaries | 8–10 in 2–3 series, elliptic to oblanceolate, 2–6 × 0.5–1.5 mm, apices acute, abaxial faces puberulent, gland-dotted. |
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Heads | in corymbiform arrays. |
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Cypselae | 2–3 mm; pappi of 30–40 bristles 3.5–4 mm. |
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Eupatorium rotundifolium |
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Distribution |
AL; AR; CT; DC; DE; FL; GA; IN; KY; LA; MA; MD; MO; MS; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WV
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Discussion | Varieties 3 (3 in the flora). Eupatorium rotundifolium is one of the more variable species of the genus; its apparent propensity to hybridize with other species has led it to be described as a compilospecies and has complicated its delimitation. Hybrids with E. perfoliatum and E. sessilifolium are sufficiently distinctive to be treated here as distinctive entities (E. ×cordigerum and E. godfreyanum, respectively), and the varieties ovatum and scabridum have also been proposed to be of hybrid origin. The boundaries between varieties are indistinct and individual specimens may be difficult to place with confidence. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 472. | ||||||||
Parent taxa | Asteraceae > tribe Eupatorieae > Eupatorium | ||||||||
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Name authority | Linnaeus: Sp. Pl. 2: 837. (1753) | ||||||||
Web links |