Symphyotrichum lanceolatum (Willd.) G.L.Nesom  
Family: Asteraceae
eastern lined aster, lance-leaved panicled aster, panicled aster, white panicle aster
[Aster lanceolatus Willd.]
Symphyotrichum lanceolatum image
Etymology: Aster: from the Greek aster, "a star," describing the radiate heads of the flowers
Plants: perennial forb
Symphyotrichum lanceolatum image
from USDA Plants website  
Symphyotrichum lanceolatum image
Symphyotrichum lanceolatum image
Symphyotrichum lanceolatum image