C0MP0S1TAE. IO29 



stem hollow, 15-60 cm. high. Leaves lanceolate, oblong or spatulate, entire, den- 

 tate, or laciniate, acute or obtuse, 5-18 cm. long, 6-30 mm. wide, or the upper 

 linear-lanceolate and small, those of the stem sessile and somewhat auriculate- 

 clasping, the basal petioled; heads numerous, 12-25 mm. broad, mostly short- 

 peduncled in a large, rather dense, terminal corymb; involucre cylindric, becom- 

 ing campanulate, 6-8 mm. high, its bracts linear, acute, more or less pubescent, 

 with no shorter outer ones; rays 15-20, pale yellow; achenes glabrous; pappus 

 white, elongated, at length twice the length of the involucre. In swamps, Iowa 

 and Wis. to Manitoba and arctic Am., west to Alaska. Reported from Lab. Also 

 in Greenland, northern Europe and Asia. June-Aug. 



20. Senecio lobatus Pers. Butterweed. Cress-leaved Groundsel. (I. F. 

 f. 4050.) Annual, glabrous throughout, or slightly woolly when young, fleshy and 

 tender; stem hollow, simple or branched, 3-9 dm. high. Leaves 5-25 cm. long, 

 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, 14-20 mm. broad, slender-peduncled in 

 terminal corymbs; involucre nearly cylindric, 5 mm. high, its bracts linear, acute, 

 usually with no smaller outer ones; rays 6-12; achenes minutely hispidulous on 

 some of the angles. In swamps, Mo. and southern 111. to N. Car., N. Mex., Mex. 

 and Fla. April-Sept. 



21. Senecio Jacobaea L. Tansy Ragwort. Staggerwort. (I. F. 

 f. 4051.) Perennial by short thick rootstocks, somewhat woolly, or glabrous; 

 stems stout, simple, or branched above, 6-12 dm. high, very leafy. Leaves 5-20 

 cm. long, the lower petioled, the upper sessile, the lobes oblong-cuneate, dentate or 

 incised; heads very numerous, 12-16 mm. broad, short-peduncled in large com- 

 pact corymbs; involucre narrowly campanulate, about 5 mm. high, its bracts linear- 

 lanceolate, acute, green, or tipped with black; rays 12-15; achenes of the disk- 

 flowers pubescent, those of the rays glabrous. In waste places, N. S., N. B. and 

 Ont., and in ballast about N. Y. and Philadelphia. Adventive from Europe. 

 July-Sept. 



22. Senecio sylvaticus L. Wood Groundsel. (I. F. f. 4052.) Annual; 

 stem usually much branched, 3-7 dm. high, leafy. Leaves 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 4 mm. broad; involucre usually swollen at the 

 base; rays none, or very short and recurved; achenes canescent. In waste places, 

 N. S. and Pr. Edw. Isl. to Me. Also on the coasts of Cal. and Br. Col. Nat. or 

 adventive from Europe. April-Sept. 



23. Senecio vulgaris L. Common Groundsel. (I. F. f. 4053.) Annual; 

 stem hollow, usually much branched, 1. 5-3. 5 dm. high. Leaves 5-15 cm. 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 6 mm. broad; bracts of the involucre linear, 

 often blackish-tipped; rays none; achenes slightly canescent. In cultivated ground 

 and waste places, Newf. and Hudson Bay to Va., west to Mich, and S. Dak. Also 

 on the Pacific Coast. Nat. from Europe. April-Oct. 



24. Senecio viscosus L. Fktid or Viscous Groundsel. (I. F. f. 4054.) 

 Annual, strong-scented; stem usually much branched, 3-6 dm. high. Leaves 1-2- 

 pinnatifid, 4-7 cm. long, oblong or somewhat spatulate in outline, the segments 

 oblong or cuneate, dentate or incised; lower leaves petioled; heads few in the cor- 

 ymbs, 6-8 mm. broad, mostly slender-peduncled; involucre nearly cylindric, 8-IO 

 mm. high, its bracts linear, acute, usually with 1-3 shorter outer ones; rays com- 

 monly about 20, very short, recurved and inconspicuous; pappus about one-third 

 longer than the involucre. In waste places and on ballast near the coast, N. B. to 

 N. Car. July-Sept. 



97. ARCTIUM L. 



Large coarse branching, rough or canescent, mostly biennial herbs, with broad 



alternate petioled leaves, and rather large heads of purple or white perfect tubular 



flowers, racemose, corymbose or paniculate at the ends of the branches. Involucre 



subglobose, its bracts rigid, lanceolate, tipped with spreading or erect hooked bristles, 



