Symphyotrichum turbinellum (Lindl.) G.L. Nesom

Prairie Aster

© SRTurner

Family - Asteraceae/Astereae

Habit - Perennial forb with a compact, woody, sometimes short-branched, usually horizontal rootstock.

Stem - Spreading to ascending, to 1.2 m, single or multiple, usually branched, sparsely pubescent toward the tip with spreading, often stout and stiff (sandpapery) hairs, these often in lines, usually glabrous toward the base.

	Stem and nodes.
© SRTurner

Leaves - Alternate, simple, sessile to short-petiolate. Basal and lower stem leaves often absent at flowering. Stem leaves to 12 cm long and 2 cm wide, narrowly oblanceolate, elliptic, or oblong, tapered at base, the margins entire or sparsely toothed, the upper surface glabrous and somewhat glossy, the undersides glabrous except along midvein. Upper stem leaves reduced, sessile but not clasping.

	Stem and leaves.
© SRTurner

	Leaf adaxial.
© SRTurner

	Leaf abaxial.
© SRTurner

Inflorescences - Open panicles of heads, sometimes with relatively long, loosely racemose branches, the heads appearing mostly long-stalked, the bracts usually noticeably shorter and narrower than the adjacent foliage leaves, 0.2-0.7 cm long, narrowly lanceolate to more commonly linear.

	Inflorescence.
© SRTurner

Heads - Radiate, mostly 2-3 cm in diameter. Involucre 7-12 mm long, the bracts in 6-9 unequal, overlapping series. Involucral bracts narrowly oblong-oblanceolate to oblanceolate, rounded or broadly angled to a bluntly pointed and ascending tip, the base somewhat thickened and keeled, the slender midvein broadened relatively abruptly in the apical 1/5-1/3 into a broadly elliptic to diamond-shaped or obovate green tip, the outer surface glabrous or less commonly sparsely hairy toward the tip, the margins usually finely hairy, especially toward the tip.

	Flowering heads.
© SRTurner

	Flowering head.
© SRTurner

	Involucre.
© SRTurner

Flowers - Ray florets 14-20 in 1 series, pistillate, the corollas well developed, 10-16 mm long, lavender to purple to bluish purple. Disc florets 15-30, perfect, yellow turning reddish-brown after pollination, the corollas 4.5-6.5 mm long, the slender portion of the tube shorter than the slightly expanded apical portion, the lobes 0.6-0.9 mm long, 17-22 percent of the total length of the expanded portion. Pappus bristles 4.5-6.0 mm long, off-white to light tan.

	Florets.
© SRTurner

Fruits - Achenes 2-3 mm long, with 4 or 5 longitudinal ribs, purplish brown to brown, sparsely hairy.

Flowering - August - November.

Habitat - Forest openings, savannas, glades, ledges and tops of bluffs, railroads, roadsides. Prefers acidic substrates.

Origin - Native to the U.S. Midwest.

Other info. - This aster occurs throughout much of Missouri, though it is apparently absent from the northwestern quadrant of the state and a portion of the central Ozarks. Missouri is at the center of the plant's natural range, which extends to only a few surrounding states. It is a relatively easy aster to recognize, having long involucres and elliptic leaves with tapered bases. The plants tend to have a branched, open habit. The species does well in cultivation. It is showy with relatively large heads and is worthy of more frequent cultivation in gardens and landscapes.

The common name "prairie aster" is not really appropriate, since the plant is not generally found in prairies. The epithet turbinellum means "top-shaped," apparently referring to the involucres.

Photographs taken at Taum Sauk State Park, Iron County, MO, 9-27-2010 and 9-19-2012, Shaw Nature Reserve, Franklin County, MO, 10-4-2016, and Little Lost Creek Conservation Area, Warren County, MO, 10-9-2020 (SRTurner).