Eupatorium album Linnaeus. White-bracted Thoroughwort. Phen: Late Jun-Oct. Hab: Dry woodlands. Dist: CT, NY, OH, and TN, south to FL and LA; disjunct in s. AR and n. LA (though many populations previously considered to be. E. album west of the Mississippi River are E. sullivaniae).

Origin/Endemic status: Endemic

Taxonomy Comments: E. album is a diploid/autopolyploid species and the most widespread member of the Eupatorium album complex, a group of species which have undergone extensive allopolyploid speciation. Many members of the complex have been treated as infrataxa under E. album, but are better separated as distinct species (Schilling 2011). Var. glandulosum is alleged to differ from var. album in having the involucre with copious dark glands (vs. glandless or nearly so). The distinction is dubious; variation seems essentially continuous in our area, with frequent intermediates, and there seems to be little correlation between morphology and habitat/range.

Synonymy: = Fl7, K3, K4, Tn, Schilling (2011b); < Eupatorium album L. – Oh3, Pa, RAB, S, WH3; < Eupatorium album L. var. album – Ar, C, FNA21, K1, NE, SE1, Va, W, Cronquist (1985); > Eupatorium album L. var. album – F, G, Tat, WV; > Eupatorium album L. var. glandulosum (Michx.) DC. – F, G, WV

Show in key(s)

Show parent genus

Heliophily: 8