Showy goldenrod species complex

Overview

Showy goldenrod species complex is not a taxonomic rank but an informal grouping of four morphologically similar species. Historically, they were treated as four distinct species. Later, they were treated as four varieties of a single species. A recent study (Semple et al. 2017) examined multiple variables of the complex, and the authors proposed restoring each variety to full species rank. The proposal was not widely adopted at first, but it has been steadily gaining acceptance.

Plants in this complex are found in open woodlands, fields, prairies, thickets, and roadsides. They grow under full sun in moderately moist to slightly dry conditions in sandy, gravelly, or loamy soil. They bloom from late July or early August to early October. As the name suggests, the plant is very showy when in bloom.

Description

In the field, it is easy to identify a plant that belongs to this group. The stems and leaves are hairless below the inflorescence. The stems are finely ridged. They are not shiny, and they are not covered with a whitish waxy bloom (glaucous). The margins of the middle and upper stem leaves are not toothed. The inflorescence is an elongated branched panicle, not pyramidal or nodding. The branches of the inflorescence curve upward, not outward or downward. Each branch of the inflorescence is spike-like with flower heads oriented in several directions.

Distribution

Sources

2, 7, 24, 28, 30, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 10/10/2026).

Midwest Herbaria Portal. 2026. https://midwestherbaria.org/portal/index.php. Accessed 10/10/2026.