Symphyotrichum oblongifolium (Aromatic Aster)
|Also known as:||Fall Aster|
|Habitat:||sun; dry sandy or rocky soil; prairies, outcrops, open woods, dunes, roadsides|
|Bloom season:||September - October|
|Plant height:||1 to 2 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Branching clusters of stalked flowers at the top of the stem and arising from upper leaf axils. Branches are initially spreading, becoming ascending to nearly erect. Flowers are 1 to 1½ inches across, with 20 to 35 petals (ray flowers), and a bright yellow center disk that turns reddish with age. Ray color ranges from lavender to purple to deep violet.
The bracts (phyllaries) surrounding the base of the flower are in 4 to 6 layers, typically lance-linear, pale green with widely spreading darker green tips, though may be broader and more like the bracts along the flower stalk. Phyllaries have minute hairs around the edge and may be covered in glandular hairs. Flower stalks are up to 2 inches long, covered in a mix of glandular and stiff, non-glandular hairs, with a dense covering of small, narrow, leaf-like bracts that are widely spreading to curled back at the tip.
Leaves and stem:
Leaves are mostly oblong, up to 2½ inches long and less than ½ inch wide, pointed at the tip, rough textured from short hairs, toothless but with minute hairs around the edge, and are stalkless. Basal leaves are more spatula-shaped and typically wither away by flowering time but may persist. Leaves become progressively smaller as they ascend the stem and are reduced to bracts in the flowering branches. Stems are single or multiple from the base, ascending to erect or prostrate but rising at the tips (decumbent), slender and brown, hairless near the base and variously covered in a mix of glandular and stiff, non-glandular hairs in the upper plant. Plants tend to form colonies from thin, woody rhizomes.
Fruit is a dry seed with a tuft of light brown hairs to carry it off in the wind
This is one of the last flowers to bloom in late summer through fall. There is no floral scent, but the leaves give off a pleasant aroma when crushed, and is where the common name comes from. Aromatic Aster most closely resembles Silky Aster (Symphyotrichum sericeum) which has no glandular hairs, leaves that are smaller and silky hairy, much wider phyllaries, and the flower center disk is pale yellow.
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Photos by K. Chayka taken at Fort Snelling State Park, Hennepin County, and Seven Sisters Prairie, Otter Tail County. Photos courtesy Peter M. Dziuk taken in Washington County and outside the DNR St Paul office.
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