482 



COMPOSITAE. 



[Vol. III. 



Senecio Jacobaea L,. Tansy Ragwort. Staggerwort. (Fig. 4051.) 



Senecio Jacobaea L. Sp. PI. 870. 1753. 



Perennial by short thick rootstocks, some- 

 what woolly, or glabrous; stems stout, simple, or 

 branched above, 2-4 high, very leafy. Leaves 

 2-pinnatifid, 2 / -8 / long, the lower petioled, the 

 upper sessile, the lobes oblong-cuneate, den- 

 tate or incised; heads very numerous, 6 // -8 // 

 broad, short-peduncled in large compact corymb; 

 involucre narrowly companulate, about 2_^ // 

 high, its bracts linear-lanceolate, acute, green, or 

 tipped with black, usually with a few subulate 

 outer ones; rays 12-15; achenes of the disk- 

 flowers pubescent, those of the rays glabrous; 

 pappus white. 



In waste places, Nova Scotia, New Brunswick 

 and Ontario, and in ballast about New York and 

 Philadelphia. Adventive from Europe. Called also 

 Staverwort, Cankerweed, Kettle-dock, St. James'- 

 wort, Felon-weed, Fairies' Horse, Ragweed. July- 

 Sept. 



20. Senecio sylvaticus L. Wood 

 Groundsel. (Fig. 4052.) 



Senecio sylvaticus L. Sp. PI. 868. 1753. 



Annual, glabrous or puberulent; stem usually 



much branched, i-2}4 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 7/ 



broad, 3 // -4 // high; involucre usually quite 



naked and swollen at the base; rays none, or 



very short and recurved; achenes canescent; 



pappus white. 



In waste places, Nova Scotia and Prince Edward 

 Island. Also on the coasts of California and British 

 Columbia. Naturalized or adventive from Europe. 

 April-Sept. 



21. Senecio vulgaris L,. Common 

 Groundsel. (Fig. 4053.) 



Senecio vulgaris L. Sp. PI. 867. 1753. 



Annual, puberulent or glabrate; stem hollow, 

 usually much branched, (y'-\$' 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 in- 

 cised, their segments oblong, dentate; heads 

 several or numerous in the corymbs, nearly 3 // 

 broad, 4 // -6 // high; bracts of the involucre linear, 

 often blackish-tipped, almost always with a few 

 subulate outer ones; rays none; achenes slightly 

 canescent; pappus white. 



In cultivated ground and waste places, New- 

 foundland and Hudson Bay to Virginia, west to 

 Minnesota and Michigan. Also on the Pacific 

 Coast Naturalized from Europe. Other names 

 are Grinsel, Simson, Birdseed, Chickenweed. 

 April-Oct. 



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