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..
Senecio vulgaris L. Sp. Pl. 867. 1753.
Annual, puberulent or glabrate; stem hollow, usually much branched, 6'-15' high. Leaves pinnatifid, 2'-6' long, the lower spatulate in outline, petioled, obtuse, the upper sessile or clasping at the base, more deeply lobed or incised, their segments oblong, dentate; heads several or numerous in the corymbs, nearly 3" broad, 4"-6" high; bracts of the involucre linear, with few or several subulate black-tipped outer ones; rays none; achenes slightly canescent; pappus white.
In cultivated ground and waste places, Newfoundland to Hudson Bay, North Carolina, Minnesota, Michigan, and west to the Pacific Coast. Bermuda. Naturalized from Europe. Other names are grinsel, simson, birdseed, chickenweed. April-Oct.
Senecio sylvaticus L. Sp. Pl. 868. 1753.
Annual, glabrous or puberulent; stem usually much branched, 1°- 2 1/2° high, leafy. Leaves pinnatifid, oblong or lanceolate in outline, the segments oblong or spatulate, obtuse, dentate, lobed or entire, or the uppermost leaves linear and merely dentate; heads several or numerous in the corymbs, slender-peduncled, about 2" broad, 3"- 4" high; involucre usually quite naked and swollen at the base; rays very short and recurved; achenes canescent; pappus white.
In waste places Newfoundland to Nova Scotia, Quebec and Maine. Also on the coasts of California and British Columbia. Naturalized or adventive from Europe. April-Sept.
Senecio viscosus L. Sp. Pl. 868. 1753.
Annual, viscid-pubescent, strong-scented; stem usually much branched, 1°-2° high. Leaves 1-2-pinnatifid, 1 1/2' - 3' long, oblong or somewhat spatulate in outline, the segments oblong or cuneate, dentate or incised; lower leaves petioled; heads few in the corymbs, 3"-4" broad, mostly slender-peduncled; involucre nearly cylindric, 4"-5" high, its bracts linear, acute, with 1-3 shorter outer ones; rays commonly about 20, very short, recurved and inconspicuous; achenes glabrous; pappus bright white, about one-third longer than the involucre.
In waste places and on ballast near the coast, Nova Scotia, New Brunswick and Quebec to North Carolina. July-Sept.
Annual, glabrous throughout, or slightly woolly when young, fleshy and tender; stem hollow, simple or branched, 1°-3° high. Leaves 2'-10' long, pinnately divided, the segments orbicular, oblong, obovate or cuneate, obtuse, sinuate-dentate, entire or lobed, the terminal segment usually larger than the others; lower and basal leaves slender-petioled; heads numerous, 7"-10" broad, slender-peduncled in terminal corymbs; involucre nearly cylindric, 1 1/2" high, its bracts linear, acute, usually with no small outer ones; rays 6-12; achenes minutely hispidu-lous on some of the angles; pappus white, somewhat longer than the involucre.
In swamps, North Carolina to Kentucky, Illinois, Missouri, Arkansas, Florida, New Mexico and Mexico. April-Sept.