Symphyotrichum ascendens. Synonym: Aster ascendens. (Western Aster)
Asteraceae (Sunflower Family)

Foothills, montane. Woodlands, openings, roadsides. Summer, fall.
East Fork Trail, August 28, 2015.

Foothills, montane. Woodlands, openings, roadsides. Summer, fall.
East Fork Trail, August 28, 2015.

Symphyotrichum ascendens can grow to three or four feet tall, has multiple flower heads, and often occurs in patches.

Welsh indicates that this species "is the most common, most widespread, most commonly collected, and most variable aster species, having been named not fewer than sixteen times". It is most easily distinguished from its similar cousins by its shingled phyllaries and the obtuse tip of the outer phyllaries (see below).

Linnaeus named the Aster genus in 1753 and John Lindley named this species in 1834 from a specimen collected by Drummond on the banks of the Saskatchewan.  In 1995 Guy Nesom proposed moving many members of the Aster genus to Symphyotrichum and that proposal is now accepted by most botanists. 

Trichomes are hairs and "symphy" means "coming together".  So "Symphyotrichum" refers to hairs growing together, probably referring to the line of hairs common on this species. "Ascendens" is Latin for "rising upwards", perhaps referring to the upward pointing leaves or the tall and upright stature of this Symphyotrichum species.

Symphyotrichum ascendens. Synonym: Aster ascendens. (Western Aster)
Asteraceae (Sunflower Family)

Foothills, montane. Woodlands, openings, roadsides. Summer, fall.
East Fork Trail, August 28, 2015.

The key characteristic separating S. ascendens from similar species is the shingled phyllaries. The white arrows point to the phyllaries which overlap each other like shingles on a roof. Another distinguishing characteristic is the rounded tips of the outer phyllaries (see the phyllary pointed to by the bottom).

Ray flowers are purple to violet or pink, rarely white.

Symphyotrichum ascendens. Synonym: Aster ascendens. (Western Aster)
Asteraceae (Sunflower Family)

Foothills, montane. Woodlands, openings, roadsides. Summer, fall.
East Fork Trail, August 28, 2015.

Leaves vary widely from less than a centimeter long to over 15 centimeters long and hairiness varies also, from glabrous to pubescent, but leaves are usually ciliate, i.e., fringed with hairs. Lower leaves are often larger than upper ones, are often deciduous at anthesis (flowering time), and are commonly petiolate (whereas upper leaves are often sessile).

Stems hairs and leaf hairs are, strigose, i.e., short, pointed, and appressed.

Range maps © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Symphyotrichum ascendens