Symphyotrichum is a genus of perennial herbs. Formerly part of the genus Aster.
Leaves alternate, simple, entire to toothed or lobed.
Flowers small, in compact heads that arise from a floral base (involucre) consisting of one or more rows of small bracts (phyllaries); both bracts and flowers are attached to the expanded tip of the flower stem (receptacle); flowers are tubular and of two forms: radially symmetrical disk flowers: yellow, usually becoming red-purple in age, (perfect: both male and female functions), and bilaterally symmetrical ray flowers, mostly white to blue or purple, with one enlarged (united) petal (pistillate: female); in our Asters flower heads consist of an outer ring of rays around a center of disk flowers; flower heads mostly in branched clusters, or sometimes solitary.
Fruit dry, small, one-seeded (achene), with a plume of bristles (pappus); wind dispersed. Blooming mostly Aug.-Nov.
Origin: All our Symphyotrichums are native to this region.
Notes: Recent changes in taxonomic classification have broken this genus into at least six different genera, eliminating the genus Aster altogether. Those in New York City fall into Symphyotrichum, Oclemen, Doellingeria, Sericocarpus, and Eurybia genera. This new taxonomy will be seen by many as difficult and unnecessary as outlined by Andrew Greller (2006) in his review of “Wildflowers in Field and Forest,” (Clemants and Gracie 2006). However, the new system is now used in the USDA PLANTS Database (2006). The differences among these new genera are mostly technical and difficult to tease out for non-taxonomists. Symphyotrichum is used as food by Schinia arcigera (arcigera flower moth) larva.