What is "symphyotrichum"

Symphyotrichum is a genus of about 90 species of herbaceous annual and perennial plants in the composite family (Asteraceae) that were formerly treated within the genus Aster. The majority are endemic to North America, but several species also occur in the West Indies, Central and South America, as well as in eastern Eurasia. Many species have been introduced to Europe as garden specimens, most notably the New England aster (Symphyotrichum novae-angliae) and the New York aster (Symphyotrichum novi-belgii).