Eupatorium truncatum Muhl. ex Willd.


Eupatorium xtruncatum plant

Family - Asteraceae/Eupatorieae

Habit - Forb.

Stems - Ascending to erect, to 1 m, moderately to densely pubescent with curled to spreading hairs, sometimes branched in upper half.

Eupatorium xtruncatum stem

Leaves - Opposite, sessile, simple, lanceolate to elliptic to obovate, the bases sessile and often expanded but not perfoliate, the margins entire or toothed, the abaxial surface finely pubescent.

Eupatorium xtruncatum leaves

Eupatorium xtruncatum leaf2

Inflorescence - Terminal corymbiform panicle of heads. Involucral bracts lanceolate, hairy.

Eupatorium xtruncatum inflorescence

Eupatorium xtruncatum involucres

Heads - Discoid, typically containing 8-11 florets.

Eupatorium xtruncatum florets

Fruits - No info yet.

Flowering - August - September.

Habitat - Forest margins, roadsides, ditches, moist disturbed areas.

Origin - Native to the U.S.

Lookalikes - Eupatorium serotinum, E. perfoliatum, other members of the genus.

Other info. - This plant is a hybrid between Eupatorium serotinum and E. perfoliatum. It has been collected in a few widely scattered locations throughout Missouri and eastward to the Atlantic coast. It is uncommon nearly everywhere. The plant seems to pop up sporadically (but rarely) when the two parents grow within reasonable proximity to each other.

Most Eupatorium keys, when applied to this plant, will lead to E. perfoliatum; however, this plant is much different from the typical E. perfoliatum. The leaf bases are tapered and not perfoliate around the stem, and they lack the pronounced rugose surface texture of E. perfoliatum leaves.

Photographs taken at Big Cane Conservation Area, Butler County, MO, 9-7-2019 (SRTurner).