Symphyotrichum undulatum (formerly Aster undulatus) 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 30and.
Symphyotrichum undulatum is a perennial, herbaceous plant that flowers from August through October, growing to heights between 30and from a cespitose rootstock. The roots can have short rhizomes or branched and woody caudices.
Its flowers have blue to purple, or sometimes lilac, ray florets and cream or light yellow, then purple, disk florets.
The fruits (seeds) of Symphyotrichum undulatum are not true achenes but are cypselae, resembling an achene but surrounded by a calyx sheath. This is true for all members of the Asteraceae family. After pollination, they become dull purple to light brown or tan with an oblong-obovoid compressed shape, in length with nerves, and with a few stiff, slender bristles on the surface (strigillose). They also have tufts of hairs (pappi) which are cream or rose-tinged and in length.
The species has a monoploid number (also called base number) of eight chromosomes Individual plants with 16 and 32 sets of its chromosomes have been found, meaning the species is diploid and tetraploid.
, NatureServe listed as Secure (G5) globally; Secure (S5) in New Jersey, New York, North Carolina, and West Virginia; Apparently Secure (S4) in Virginia; Vulnerable (S3) in Indiana and Nova Scotia; and, Critically Imperiled (S1) in Illinois. The species' global status was last reviewed on 25 July 2016.