Eupatorium hyssopifolium L.
Family - Asteraceae
Stems - Erect, to 1 m, moderately to densely short-hairy.
Leaves - Mostly in whorls of 3-4, sessile, linear to oblong-elliptic, entire or with a few shallow teeth, often revolute, variously pubescent, gland-dotted, with single midvein. Nodes usually with fascicles of axillary leaves.
Inflorescence - Terminal panicles, +/- flat-topped.
Involucre - Narrowly cup-shaped, 4-6 mm long. Bracts with blunt tips.
Ray flowers - Absent.
Disk flowers - Disk florets 5 per head, with corollas 3.5-4.0 mm, often glandular, white. Styles exserted at anthesis.
Flowering - August - November.
Habitat - Dry open ground surrounding upland sinkhole ponds.
Origin - Native to U.S.
Other info. - This showy species is rare in Missouri, being found in only a few counties
in the eastern Ozark division. This species is common in the Coastal Plain of the eastern U.S. and has been slowly extending its range northward. The
Missouri plants are considered to be var. calcaratum Fernald & B.G. Schub. Other infraspecific forms are recognized by many
authors, however, there is significant intergradation. The species can hybridize with other members of the Eupatorium genus,
giving apparently fertile forms with intermediate morphology.
Photographs taken in the Croatan National Forest, NC., 10-20-02.