Most of the identification aids that I use, identify this flower as Aster pratense. This member of the Aster family has been renamed Symphotrichium pratense during the thirty years since my references were published. I mention this a caution to scientist and layman; overtime, new information can lead to scientific names changing because of new information or corrections for errors in naming committed by previous workers.
This beautiful, large flowered aster (1.25 inch diameter) can be found in sandy or sandy loam soils in grasslands or open woodlands. They can attain 32 inches in height and produce narrow, pointed leaves that are stalkless and alternate along their stems. The lavender petals of the ray flowers are distinctive and contrast with their yellow or reddish brown disk flowers.
Symphotrichium pratense blooms late in the growing season between September and November bringing delightful color to a drab, dried out fall landscape. The photos shown here were taken in early November.