Eupatorium torreyanum Short & R. Peter. Common name: Torrey's Eupatorium. Phenology: Late Jul-Oct. Habitat: Dry woodlands, powerline rights-of-way, roadsides, marshes. Distribution: NY south to n. peninsular FL, Panhandle FL, and west to OH, TN, and LA.
Origin/Endemic status: Endemic
Taxonomy Comments: Cronquist (1980) considers this taxon a "well-marked variety", "probably originated through hybridization between E. hyssopifolium and some other species, but now a stable entity". The other parent is postulated by Sullivan (1978) to be E. semiserratum. For reasons stated in the comments before the species accounts, the taxon is here treated as a species.
Synonymy ⓘ: = K4, NE, NY, S, Tat, Tn, Va; = Eupatorium hyssopifolium L. var. laciniatum Gray — Ar, C, F, Fl7, FNA21, G, Oh3, SE1, W, WH3; < Eupatorium hyssopifolium L. — Pa, RAB. Basionym: Eupatorium torreyanum Short & R.Peter 1836
Links to other floras: = Eupatorium hyssopifolium var. laciniatum - FNA21
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Heliophily ⓘ: 8
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Horticultural Information
Intro: Erect perennial of dry woodlands, powerline rights-of-way, roadsides and marshes.
Stems: Stems mostly solitary, branched above, rough-hairy (especially above).
Leaves: Leaves in whorls of 3 or opposite, sessile, lance-shaped, 2-4 1/2 in. long, with 3 prominent veins, with widely spaced teeth on the margins and rough-surfaced.
Inforescence:
Flowers: Composite flowers (heads) arranged in flat-topped clusters at tips of branches; heads white, consisting of several tiny, tubular disk florets with 5-lobed corollas. Several series of tiny, green and white bracts surround the base of each head.
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Height: 2-4 ft.
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description: Erect perennial of dry woodlands, powerline rights-of-way, roadsides and marshes.
stems: Stems mostly solitary, branched above, rough-hairy (especially above).
leaves: Leaves in whorls of 3 or opposite, sessile, lance-shaped, 2-4 1/2 in. long, with 3 prominent veins, with widely spaced teeth on the margins and rough-surfaced.
inflorescence:
flowers: Composite flowers (heads) arranged in flat-topped clusters at tips of branches; heads white, consisting of several tiny, tubular disk florets with 5-lobed corollas. Several series of tiny, green and white bracts surround the base of each head.
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