This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Aster .ardiflorus L. Sp. Pl. Ed. 2, 1231. 1763.
Aster patulus Lam. Encycl. 1: 308. 1783.
Stem glabrous, slightly pubescent, or villous, corymbosely branched near the summit, 1°-3° high. Leaves lanceolate, oblong-lanceolate, or ovate-lanceolate, serrate with low teeth, or some of them entire, acuminate at the apex, narrowed into a slightly clasping base, or the lower into winged petioles, glabrous or nearly so on both sides, rough-ish-margined, 3'-6' long, 4"-10" wide; heads about 1' broad, not very numerous, involucre hemispheric, its bracts often 6" long, acute, somewhat unequal; rays 20-30, violet; pappus nearly white; achenes pubescent.
Along streams, New Brunswick to Pennsylvania. Aug.-Oct.
Stem glabrous, or pubescent in lines above, flexuous, much branched, 1°-2° high. Leaves thin, oblong to ovate-lanceolate, or lanceolate, sharply and coarsely serrate, scabrous above, glabrous or nearly so beneath, 3'-8' long, 9"-18" wide, acuminate at the apex, abruptly narrowed below into a broad margined entire petiole, the base auriculate-clasping; heads usually numerous, 1'broad or more; involucre hemispheric, its bracts linear, acute, green, spreading, imbricated in 3 or 4 series, the outer shorter; rays 20-30, violet, 4"-6" long; pappus tawny; achenes pubescent.
In moist soil, Massachusetts to Minnesota, Virginia, Kentucky and Iowa. Aug.-Oct.
Aster schistdsus Steele, of West Virginia, is intermediate in characters between this species and A. Lowrieanus Porter, and may be a hybrid.
Aster laevis L. Sp. Pl. 876. 1753.
Aster laevis amplifolius Porter, Mem. Torr. Club 5:
Stem usually stout, glabrous, often glaucous, 2°-4° high, branched or simple. Leaves thick, entire, or serrate, glabrous, slightly rough-margined, the upper all sessile and usually cordate-clasping, lanceolate, oblong-lanceolate, oblanceolate or ovate, acute or obtusish, 1'-4 long, 4"-2' wide, the basal and lower gradually narrowed into winged petioles, those of the branches often small and bract-like; heads usually numerous, about 1' broad; involucre campanulate, its bracts rigid, acute, appressed, green-tipped, imbricated in several series; rays 15-30, blue or violet; pappus tawny; achenes glabrous or nearly so.
Usually in dry soil, Maine to Ontario, Virginia, Alabama, Louisiana, Saskatchewan, Missouri and Colorado. Races differ in leaf-form. Sept.-Oct.