Symphyotrichum is a genus of over 100 species and naturally occurring hybrids of herbaceous annual and perennial plants in the composite family, Asteraceae, most which were formerly treated within the genus Aster. The majority are endemic to North America, but several also occur in the West Indies, Central and South America, as well as one species in eastern Eurasia. Several species have been introduced to Europe as garden specimens, most notably New England aster and New York aster.
Canadanthus is a North American monotypic genus of flowering plants in the family Asteraceae. The only species is Canadanthus modestus, commonly known as great northern aster or western bog aster. It is native to most of Canada and to northern parts of the United States.
Symphyotrichum depauperatum, commonly known as serpentine aster or starved aster, is a rare species in the family Asteraceae adapted to serpentine barrens, an ecosystem with a high concentration of toxic metals in the soil. It has been found in Pennsylvania, Maryland, and on some diabase glades in North Carolina. It grows to 50 centimeters and has white ray florets surrounding a center of yellow disk florets.
Symphyotrichum falcatum is a species of flowering plant in the family Asteraceae. Commonly called white prairie aster and western heath aster, it is native to a widespread area of central and western North America.
Symphyotrichum urophyllum is a species of flowering plant in the family Asteraceae native to eastern North America, commonly known as arrowleaf aster.
Symphyotrichum racemosum is a species of flowering plant native to parts of the United States and introduced in Canada. It is known as smooth white oldfield aster and small white aster. It is a perennial, herbaceous plant in the family Asteraceae. It is a late-summer and fall blooming flower.
Symphyotrichum rhiannon is a species of flowering plant endemic to a serpentine barren in western North Carolina. It has been given the vernacular Rhiannon's aster and is also known as Buck Creek aster. It is a perennial, herbaceous plant in the family Asteraceae.
Symphyotrichum ciliatum is a species of flowering plant in the family Asteraceae native to North America and eastern Eurasia. Commonly known as rayless annual aster and rayless alkali aster, it is an annual, herbaceous plant that may reach over 70 centimeters in height. Each flower head has many whitish then pink disk florets and no ray florets ("rayless").
Symphyotrichum simmondsii is a species of flowering plant of the family Asteraceae endemic to the southeastern United States. Commonly known as Simmonds' aster, it is a colony-forming herbaceous perennial.
Symphyotrichum fontinale is a species of flowering plant in the family Asteraceae endemic to Florida and a small area of southwest Georgia. It has the common names of Florida water aster and Florida water American-aster. S. fontinale is a perennial, herbaceous plant that may reach 30–90 centimeters in height.
Symphyotrichum yukonense is a species of flowering plant in the family Asteraceae endemic to disjunct areas in Alaska and the Canadian territories of Yukon and Northwest Territories. Commonly known as Yukon aster, it is a perennial, herbaceous plant 5 to 30 centimeters in height. Its flowers have purple to blue ray florets and yellow to brown disk florets. S. yukonense grows at elevations of 300–1,500 meters in mud flats and on sandy or silty lake shores. It is a NatureServe Vulnerable (G3) species and is classified Imperiled (S2) in its Canadian range.
Symphyotrichum foliaceum is a species of flowering plant in the family Asteraceae native to western North America. Its common names are leafy aster, leafy-bracted aster, and alpine leafybract aster, and it is a perennial, herbaceous plant that may reach heights from 10 to 60 centimeters. Its flowers have violet to purple ray florets and yellow disk florets.
Symphyotrichum retroflexum is a species of flowering plant in the family Asteraceae native to the southeastern United States. Commonly known as rigid whitetop aster, it is a perennial, herbaceous plant that may reach 40 to 100 centimeters tall. Its flowers have blue to purple ray florets and cream to pale yellow then pinkish disk florets. It is known only from the Blue Ridge Mountains in Alabama, Georgia, North Carolina, South Carolina, Tennessee, and Virginia, where it grows in wooded areas at elevations of 400–1,500 meters. As of September 2021, NatureServe classified it as Apparently Secure (G4); it had been reviewed last in 1994 and is marked as "needs review". There is an introduced presence of S. retroflexum in southeast China.
Symphyotrichum fendleri is a species of flowering plant in the family Asteraceae native to the mid- and south-central United States, including Great Plains states and extending into Texas and New Mexico. Commonly known as Fendler's aster, it is a perennial, herbaceous plant that may reach 6 to 30 centimeters in height. Its flowers have lavender to purple ray florets and yellow then reddish purple disk florets.
Symphyotrichum undulatum is a species of flowering plant in the family Asteraceae native to eastern North America. Commonly known as wavyleaf aster, it is a perennial, herbaceous plant that flowers August through October and may reach heights between 30 and 160 centimeters.
Symphyotrichum spathulatum is a species of flowering plant in the family Asteraceae native to western North America including northwestern Mexico. Commonly known as western mountain aster, it is a perennial, herbaceous plant that may reach 20 to 80 centimeters tall. Its flowers, which open in July and August, have violet ray florets and yellow disk florets.
Symphyotrichum subspicatum is a species of flowering plant in the family Asteraceae native to western North America. Commonly known as Douglas's aster, it is a perennial, herbaceous plant that may reach 40 to 120 centimeters tall. Its flowers have violet ray florets and yellow then reddish disk florets.
Symphyotrichum walteri is a species of flowering plant in the family Asteraceae native to the southeastern United States. Commonly known as Walter's aster, it is a perennial, herbaceous plant that may reach 20 to 100 centimeters tall. Its flowers have bluish-purple ray florets and yellow disk florets.
Symphyotrichum parviceps is a species of flowering plant in the family Asteraceae. It is native to the central United States, and it has the common names of smallhead aster and small white aster. A usually short-lived herbaceous, perennial plant, it may reach 30 to 100 centimeters in height. Its flowers have white ray florets and pale yellow then purplish disk florets.
Involucre and phyllaries
Close-up of ray and disk florets
Flower heads after seeding
