Euthamia graminifolia (L.) Nutt.
Common Flat-Topped Goldenrod
CC = 3
CW = 0
MOC = 30
Family - Asteraceae/Astereae
Habit - Rhizomatous perennial forb.
Stems - Ascending to erect, to 1.5 m, usually solitary, often somewhat woody at the base, usually extensively branched above, coarsely ridged and sparsely pubescent with minute, spreading hairs, at least toward the tip.
Leaves - Alternate, simple, sessile. Lower leaves absent at flowering. Leaf blades 1-12 cm long, 1-10 mm wide, relatively thick, the margins moderately roughened with minute, stout, ascending, stiff hairs, the surfaces glabrous or sparsely pubescent with minute, spreading hairs, moderately resinous with impressed or pustular glandular dots, the smaller leaves with 1 midvein, the larger leaves with 3 or occasionally 5 main veins.
Inflorescences - Dense, flat-topped panicles of heads, these usually in clusters at the branch tips, the stalks relatively short, with relatively few leaflike bracts.
Heads - Radiate. Involucre 3-5 mm long, relatively resinous, the bracts variously rounded to sharply pointed at the tip.
Florets - Ray florets 15-25, the corollas 1-2 mm long, yellow, the short ligule ascending. Disc florets 4-10, the corolla 1.5-2.0 mm long, the lobes 0.3-0.7 mm long, yellow.
Flowering - August - October.
Habitat - Loess hill prairies, savannas, bottomland forests, roadsides.
Origin - Native to the U.S.
Lookalikes - Other species of Euthamia; more distantly, some species of Solidago.
Other info. - This relatively uncommon plant is found in scattered locations across Missouri, most commonly in northern and western regions of the state. It is recognized by its highly branched, flat-topped inflorescences of small heads, and hairy inflorescence branches. Most of the leaves, particularly well-developed lower leaves, have 3 or 5 main veins.
Photographs taken at Shaw Nature Reserve, Franklin County, MO, 8-21-2021 (SRTurner).