Symphyotrichum is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of about 90 species of herbaceous annual and perennial plants in the composite family (Asteraceae)

Asteraceae

The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

 that were formerly treated within the genus Aster. The majority are endemic in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, but several species also occur in the West Indies, Central

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 and South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, as well as in eastern Eurasia

Eurasia

Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

. Furthermore, many species have been introduced to Europe as garden specimens, most notably the New England aster

New England Aster

Symphyotrichum novae-angliae , commonly known as the New England Aster, is an herbaceous perennial in the composite family...

 (Symphyotrichum novae-angliae) and the New York aster

Symphyotrichum novi-belgii

Symphyotrichum novi-belgii also known as New York Aster is the type species for Symphyotrichum, a genus of the family Asteraceae whose species were once considered to be Asters and an ornamental plant native to Canada and the United States....

(Symphyotrichum novi-belgii).