Monographs Details: Aster
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Genus Description - Heads generally radiate, the rays pistillate and fertile, anthocyanic or white, in a few spp. reduced and inconspicuous or even wanting, the cor of the pistillate fls then a mere slender tube; invol bracts in 2 or more series, equal or more often imbricate, usually ± herbaceous at the tip and chartaceous below, sometimes herbaceous or chartaceous throughout; receptacle naked, flat or a little convex; disk-fls perfect and fertile, red or purple to yellow; style-branches flattened, with mostly narrow and acute or acuminate, externally short-hairy appendage; achenes several-nerved; pappus of numerous capillary bristles, sometimes with an additional short outer series; perennial (seldom annual) herbs, most spp. fibrous-rooted, with simple, alternate, entire or variously toothed lvs and solitary to more often several or numerous, hemispheric to subcylindric heads. (Brachyactis, Doellingeria, Ionactis, Sericocarpus) 175+, mainly N. Amer. Our spp. bloom in mid- or late summer and fall. Hybrids abound; some of the more notable ones are here formally treated. Some of the species with chromosome numbers based on x=8 (especially in the Heterophylli) tend to have additional B-chromosomes, and have often been reported to have numbers based on 9. The disk-cors characteristically consist of a slender (often short) basal tube and a more swollen limb; the lobes are part of the limb. The terms lvs basally disposed and lvs chiefly cauline are here used as explained under Solidago.
The plant traditionally called Aster (or Unamia) ptarmicoides is here referred to Solidago, in spite of its white rays. It hybridizes with several spp. of Solidago (especially of the sect. Oligoneuron), but not with Aster. It is marked by its 10–25 white rays, white disk-cors and copious (but not double) pappus with many of the bristles clavellate- thickened toward the tip.
Common Names:wild aster, Michaelmas-daisy