Genus 95.] 



THISTLE FAMILY. 



477 



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



Senecio lugens Richards. App. Frankl. Joum. Ed. 

 2: 31. 1823. 



Similar to the preceding species, more or less 

 woolly when young, soon glabrous; stem stout, 

 i-3 high. Basal and lower leaves oblong, 

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

 ticulate or dentate, 2'-$' long, ^ / -i^ / wide, 

 narrowed into margined petioles; upper leaves 

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

 or numerous, corymbose, often short-pedun- 

 cled, 6 // -io // 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 America and the Northwest 

 Territory to Minnesota, Iowa and Nebraska, west to 

 Alaska and California. June-Aug. 



5. Senecio canus Hook. Silvery 



Groundsel. (Fig. 4037.) 



5". canus Hook. Fl. Bor. Am. 1: 333. pi. 116. 1833. 



Perennial, densely and persistently white- 

 tomentose to the inflorescence; stems slender, 

 usually tufted, 6 / -i8 / high. Basal and lower 

 leaves spatulate or oval, entire, or rarely some- 

 what repand, very obtuse, i/-2 r 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 slender-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, w r est to British Columbia and California. 

 May-Aug. 



6. Senecio tomentosus Michx 



S. tomentosus Michx. Fl. Bor. Am. 2: 119. 1803. 



Perennial, more or less densely and per- 

 sistently tomentose or woolly-canescent; 

 stems rather stout, solitary, or sometimes 

 tufted, i D -2^ high. Basal and lower leaves 

 ovate-lanceolate, oblong or rarely spatu- 

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

 long, Yz'-i' wide, crenate-dentate, narrowed 

 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, S^-io" 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. 



Woolly Ragweed 



Ash wort. (Fig. 4038.) 



