Britton, Nathaniel L. & Millspaugh, Charles F. 1920. The Bahama Flora.
Description - Branching or scapose herbs, with alternate or basal leaves, and corymbose, paniculate or solitary, peduncled heads, of both tubular and radiate (rarely all tubular) flowers. Involucre hemispheric or eampanulate, its bracts narrow, nearly equal, imbricated in but 1 or 2 series in most species. Receptacle nearly flat, usually naked. Ray-flowers usually numerous, white, violet or purple, pistillate. Disk-flowers yellow, tubular, perfect, their corollas mostly 5-lobed. Anthers obtuse and entire at the base. Style-branches more or less flattened, their appendages short, mostly rounded or obtuse. Achenes flattened, usually 2-nerved. Pappus-bristles fragile, slender, scabrous or denticulate, in 1 series, or often an additional outer shorter series. [Greek, early-old, alluding to the early hoary pappus.] A genus of some 130 species, of wide distribution. Type species: Erigeron acre L.