Euthamia graminifolia (L.) Nutt.

Common Flat-Topped Goldenrod


CC = 3
CW = 0
MOC = 30

© SRTurner

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.

Euthamia_graminifolia_stem1.jpg Lower stem.

© SRTurner

Euthamia_graminifolia_stem2.jpg Upper stem.

© SRTurner

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.

Euthamia_graminifolia_leaves1.jpg Stem and leaves.

© SRTurner

Euthamia_graminifolia_leaf1.jpg Leaf adaxial.

© SRTurner

Euthamia_graminifolia_leaf2.jpg Leaf abaxial.

© SRTurner

Euthamia_graminifolia_leaf2a.jpg Leaf with five main veins.

© SRTurner

Inflorescences - Dense, flat-topped panicles of heads, these usually in clusters at the branch tips, the stalks relatively short, with relatively few leaflike bracts.

Euthamia_graminifolia_inflorescence1.jpg Inflorescence portion.

© SRTurner

Euthamia_graminifolia_inflorescence2.jpg Inflorescence portion.

© SRTurner

Heads - Radiate. Involucre 3-5 mm long, relatively resinous, the bracts variously rounded to sharply pointed at the tip.

Euthamia_graminifolia_heads.jpg Flowering heads.

© SRTurner

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.

Euthamia_graminifolia_florets.jpg Florets.

© SRTurner

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.

This species has been subdivided into infraspecific phases, but the divisions have been controversial and difficult to apply to Missouri material. The robust, upwardly hairy expression pictured above has been called var. nuttallii. Distinguishing less hairy phases from E. gymnospermoides can be difficult.

The epithet graminifolia means "grass-like leaves," which is appropriate given the long, narrow leaves of this plant.

Photographs taken at Shaw Nature Reserve, Franklin County, MO, 8-21-2021 (SRTurner).