Plains Grass-Leaved Goldenrod
Euthamia gymnospermoides
Aster family (Asteraceae)

Description: This native perennial plant is 1½–3' tall, branching frequently in the upper half to create a bushy effect. The narrow stems are hairless. The alternate leaves are up to 3½" long and less than ¼" across. They are linear, hairless, and have smooth edges. There is usually only a single prominent vein, although some of the larger leaves may have 2 additional side veins that are visible. The upper stems terminate in clusters of small composite flowers. While in the bud stage, each cluster typically has 3-7 sessile flowerheads. Some of the flowerheads eventually develop short pedicels and partially separate from each other. Each flowerhead is only 1/8" across while in bloom, and variable in length, depending on its maturity. There are about 5 yellow disk florets and 12 yellow ray florets in each flowerhead. Beneath these florets, is a short cylinder of narrow bracts. These bracts are often resinous and shiny, and can vary in color from green to pale yellow. The blooming period occurs from late summer to fall, and lasts about 2 months. A typical plant blooms gradually over a long period of time. A floral scent may, or may not, be noticeable. The florets are replaced by bullet-shaped achenes with small tufts of white hair, which are dispersed by the wind. Small brown pieces of the dried-up florets often persist within these tufts of hair. The root system is fibrous and produces long rhizomes, forming vegetative colonies readily.

Cultivation: The preference is full sun and mesic conditions. This plant isn't fussy about soil characteristics, and can flourish in sandy, gravelly, or loamy soil. The lower leaves are vulnerable to rust and sometimes fall off the stems. Otherwise, this plant presents few problems and is easy to grow – perhaps too easy, as it can spread aggressively in the average garden situation.

Range & Habitat: Plains Grass-Leaved Goldenrod occurs occasionally throughout Illinois, but is more common in the northern and western areas of the state (see Distribution Map). The distribution map is from Jones and Fuller (1955), rather than the ILPIN database (see the discussion below). Habitats include slightly moist to dry black soil prairies, sand prairies, and gravel prairies; meadows along rivers in otherwise forested areas; rocky glades; areas along roadsides and railroads, particularly where remnant prairies occur; and abandoned fields. This plant is more typical of the Great Plains to the west, but it is still locally common in some parts of the state.

Faunal Associations: The nectar or pollen of the small flowers attract an abundance of wasps, flies, and beetles, as well as some bees, small butterflies, and plant bugs. It is not unusual to find various kinds of insects hiding within the dense flowers during the day, including moths, caterpillars, and predatory insects. The foliage is eaten occasionally by mammalian herbivores, but it is not a preferred food source.

Photographic Location: The photographs were taken of plants growing in the webmaster's garden in Urbana, IL.

Comments: It appears that different authorities don't agree on the classification of specimens, and have produced different distribution maps for this species within the state. For example, Mohlenbrock (1986, 2001) and the ILPIN database restict the distribution of Euthamia gymnospermoides to the northern and western areas of the state, while Jones and Fuller (1955) and A.G. Jones (1973) state that this species occurs in other parts of the state, where it is supposed to be rather common. In my experience, these latter authorities are correct, as I have often encountered this species in east-central Illinois in prairie remnants along railroads. The Plains Grass-Leaved Goldenrod is often confused with Euthamia graminifolia (Grass-Leaved Goldenrod), and therefore its distribution within the state has been seriously underestimated. To distinguish these two species, it is necessary to count the number of florets in a sample of flowerheads. The Plains Grass-Leaved Goldenrod has 15-19 florets per flowerhead, while the Grass-Leaved Goldenrod has 20-35 florets per flowerhead (counting ray and disk florets together). Other differences between these two species include the following: 1) the former species has stems that are always hairless, while there are usually lines of hairs along the stems of the latter; 2) the former species has leaves that are more slender, usually with a single prominent vein, while the latter has leaves that usually have 3 prominent veins; and 3) the former species is usually shorter and bushier in appearance, while the latter is tall and slender. The Plains Grass-Leaved Goldenrod is also similar in appearance to Euthamia tenuifolia (Slender Grass-Leaved Goldenrod). However, this latter species is restricted to sandy prairies and dunes near Lake Michigan in Illinois. Its leaves are even more slender than the preceding Euthamia spp., and its flowerheads don't aggregrate together into the sessile clusters of the Plains Grass-Leaved Goldenrod, as described above. According to Jones and Fuller, they occur individually on separate pedicels. Older scientific names for the Plains Grass-Leaved Goldenrod are Euthamia meadia and Solidago meadia.