GE^•us 95] 



THISTLE FAMILY. 



477 



4. Senecio lugens Richards. Black- tipped Groundsel. (Fig. 4036.) 



Setiecio lugens Richards. App. Frankl. Journ. lul. 

 2: :-.i. 1S23. 



Similar to the preceding species, more or less 

 woolly when young, soon glabrous; stem stout, 

 l°-3° high. Basal and lower leaves oblong, 

 oval, or slightly spatulate, obtuse or acute, den- 

 ticulate oV dentate, 2'-^' long, y^'-i'/z' wide, 

 narrowed into margined pelioles; upper leaves 

 few, sessile, small and bract-like; heads several 

 or numerous, corymbose, often short-pcdun- 

 cled, 6"-lo" broad; involucre campanulate, 

 3"-4" high, its bracts lanceolate or oblong- 

 lanceolate, acute or obtuse, often with con- 

 spicuous black tips; rays 10-12, oblong-linear; 

 achenes glabrous; pappus white. 



In moist soil, arctic .-Vnierica and the Northwest 

 TerritorA- to Minnesota, Iowa and Nebraska, west to 

 Alaska and California. Juue-Aug. 



6. Senecio tomentosus Michx 



5. tomentosus Michx. Fl. Bor. Am. 2: 119. 



Perennial, more or less densely and per- 

 sistently tomentose or woolly-canescent; 

 stems rather stout, solitary, or sometimes 

 tufted, 1*^-2^° high. Basal and lower leaves 

 ovate-lanceolate, oblong or rarely spatu- 

 late, long-petioled, erect, very obtuse, 2'-6' 

 long, W'-2' wide, crenate-dentate, tiarrowed 

 or truncate at the base; stem-leaves few 

 and distant, small, linear-lanceolate or spatu- 

 late, crenate or rarely laciniate; heads 

 several or numerous, corymbose, mostly long- 

 peduncled. 8"-iq" broad; involucre cylindric, 

 or narrowly campanulate, its bracts linear-lan- 

 ceolate, acute or acuminate, at length glabrate, 

 with or without a few small outer ones; rays 

 10-15; achenes hispidulous, at least on the 

 angles; pappus white. 



In moist soil, southern New Jersey to Florida, 

 west to Louisiana. April-June. 



5. Senecio canus Hook. Silvery 

 Groundsel. (Fig. 4037.) 



5. cffHWiHook. Fl. Bor. Am, i: 333. pi. 116. 1833. 

 Perennial, densely and persistently white- 

 tomentose to the inflorescence; stems slender, 

 usually tufted, 5'-i8' high. Basal and lower 

 leaves spatulate or oval, entire, or rarely some- 

 what repand, very obtuse, i'-2' long, nar- 

 rowed into petioles; upper leaves oblong or 

 spatulate,obtuse or acute,mostly sessile, smaller, 

 entire or dentate; heads several or numerous, 

 8"-io" broad, usually slcnder-peduncled; in- 

 volucre campanulate, or at first short-cylindric; 

 about 5" high, its bracts linear- lanceolate, acute 

 sparingly tomentose, or glabrate, usually with 

 no exterior smaller ones; rays 8-12; achenes 

 glabrous, at least below; pappus white. 



In dry soil, Manitoba to Minnesota and Ne- 

 braska, west to British Columbia and California. 

 May-Aug. 



Woolly Ragweed. Ashwort. (Fig. 4038.) 



