Eupatorium leucolepis |
Eupatorium pilosum |
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justiceweed, white-bract thoroughwort |
ragged thoroughwort, rough boneset |
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Habit | Perennials, 40–100+ cm. | Perennials, 30–100+ cm. | ||||
Stems | (from short caudices or stout rhizomes) single, sparsely branched distally, puberulent throughout (more densely distally and among heads). |
(from short rhizomes) single, sparsely branched distally, densely puberulent to pilose throughout. |
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Leaves | usually opposite (distal sometimes alternate, ascending to vertical); sessile; blades pinnately nerved, lance-oblong to linear-oblong, 20–60 × 4–10(–15) mm, bases rounded to cuneate (not connate-perfoliate), margins entire or serrate, apices acute, faces villous (abaxial), scabrous (adaxial), gland-dotted. |
usually opposite (distal sometimes alternate); simple, sessile or subsessile; blades ± 3-nerved (distal to bases), elliptic, lanceolate, or lance-ovate, 30–90 × 20–45 mm (lengths mostly 2–2.5 times widths), bases rounded to rounded-cuneate, margins unevenly serrate, apices acute to attenuate, faces puberulent, gland-dotted. |
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Florets | 5; corollas 3–3.5 mm. |
5; corollas 3.5–4 mm. |
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Phyllaries | 8–10 in 2–3 series, narrowly elliptic, 2.5–8 × 0.8–1.2 mm, acuminate to attenuate, mucronate, abaxial faces puberulent, gland-dotted. |
7–10 in 2–3 series, oblong to lance-oblong, 2–7 × 1–1.5 mm, apices (sometimes whitish) acuminate to acute, mucronate, abaxial faces puberulent, gland-dotted. |
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Heads | in corymbiform arrays. |
in corymbiform arrays. |
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Cypselae | 2–3 mm; pappi of 30–40 bristles 4.5–5 mm. |
3–4 mm; pappi of 30–50 bristles 4–5 mm. |
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2n | = 20, 30, 40. |
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Eupatorium leucolepis |
Eupatorium pilosum |
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Phenology | Flowering Jul–Sep. | |||||
Habitat | Moist, low ground, margins of ponds, sandy soils, savannas, ditches | |||||
Elevation | 20–100+ m (100–300+ ft) | |||||
Distribution |
AL; DE; FL; GA; LA; MA; MD; MS; NC; NJ; NY; PA; RI; SC; TN; TX; VA
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AL; CT; DE; FL; GA; KY; LA; MA; MD; MS; NC; NJ; NY; PA; RI; SC; TN; VA; WV
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Discussion | Varieties 2 (2 in the flora). Eupatorium leucolepis is distinct morphologically by its acuminate to attenuate phyllaries, linear and usually plicate leaves, and phyllotaxy that is almost always strictly opposite to the arrays, with well-separated nodes. Eupatorium leucolepis has recently been shown to include two distinct species, an unnamed diploid that is endemic to Carolina Bay habitats and a series of relatively widespread and mostly polyploid, apomictic populations that include the type. It was recognized after preparation of this treatment that E. novae-angliae (E. leucolepis var. novae-angliae) was derived from hybridization between the unnamed diploid and E. perfoliatum, and is here recognized as a distinct species; it is not directly related genetically to E. leucolepis and thus is not appropriately classified as a variety of it. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eupatorium pilosum has been most commonly treated as a variety of E. rotundifolium; it is distinct morphologically by its leaves, which are narrower and 3-nerved distal to bases, rather than 3-nerved from bases. Distal leaves of E. pilosum tend to differ from the proximal by being alternate with entire margins. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 469. | FNA vol. 21, p. 471. | ||||
Parent taxa | Asteraceae > tribe Eupatorieae > Eupatorium | Asteraceae > tribe Eupatorieae > Eupatorium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | E. glaucescens var. leucolepis | E. rotundifolium var. saundersii, E. verbenifolium | ||||
Name authority | (de Candolle) Torrey & A. Gray: Fl. N. Amer. 2: 84. (1841) | Walter: Fl. Carol., 199. (1788) | ||||
Web links |