GENUS 102. 



THISTLE FAMILY. 



18. Senecio obovatus Muhl. Round-leaf 

 Squaw-weed. Fig. 4627. 



Senecio obovatus Muhl.; Willd. Sp. PI. 3: 1999. 1804. 

 Senecio Elliottii T. & G. Fl. N. A. 2 : 443. 1843. 

 5". aureus var. obovatus T. & G. loc. cit. 442. 1843. 

 5". rotundus (Britton) Small, Fl. SE. U. S. 1304. 1903. 



Perennial ; stems glabrous, or a little woolly at 

 the base, 9'-24' high. Leaves glabrous, rather thick, 

 the basal ones obovate with a cuneate base, subor- 

 bicular or broadly spatulate, very obtuse and round- 

 ed at the apex, i'-3i' long, 2-2' wide, crenate- 

 dentate, often purplish; stem leaves commonly few 

 and sessile, spatulate to oblong, often incised or 

 pinnatifid ; heads several, corymbose, 6"-8" broad, 

 about 3" high, slender-peduncled ; involucre nearly 

 cylindric, its principal bracts linear-lanceolate, 2"-3" 

 long, acute, usually with 1-3 small exterior ones; 

 rays 8-12, usually conspicuous, sometimes fewer 

 and short ; achenes glabrous ; pappus white. 



In moist soil on banks and in woods, Maine and Ver- 

 mont to Florida, Ohio, Michigan, Alabama and Texas. 

 Races differ in size, leaf-form, number and size or rays. 

 Apparently erroneously recorded from Nova Scotia and 

 Ontario. April-June. 



19. Senecio Crawfordii Britton. Crawford's 

 Squaw-weed. Fig. 4628. 



Senecio Crawfordii Britton, Torreya 1 : 21. 1901. 

 6". Balsamitae var. Crawfordi Greenman, Rhodora IO: 69. 

 1908. 



Perennial, glabrous, or with sparse woolly pubescence 

 below; stem slender, about 16' high. Leaves thick, firm, 

 the basal ones erect, the larger 8'-io' long, the blades 

 oval, oblong, or some of them narrowly obovate, mostly 

 not more than one-half as long as the slender petioles, 

 sharply and nearly equally serrate from the apex to the 

 entire cuneate base; stem leaves lanceolate or narrower, 

 mostly acuminate, incised-serrate, clasping, the upper 

 sessile, the lower petioled, the uppermost very small ; 

 heads 3-7 ; peduncles slender, bracted, rarely forked ; 

 involucre 4" high, its bracts linear-lanceolate, acumi- 

 nate, shorter than the white barbellate pappus; rays 

 4"-S" long; achenes linear, striate. 



Wet meadows, southeastern Pennsylvania. May-June. 



20. Senecio pauperculus Michx. Balsam 

 Groundsel. Fig. 4629. 



Senecio pauperculus Michx. Fl. Bor. Am. 2: 120. 



1803. 



Senecio Balsamitae Muhl. ; Willd. Sp. PI. 1999. 1804. 

 Senecio aureus var. Balsamitae T. & G. Fl. N. A. 2 : 



442. 1843. 



Perennial, often tufted; stems slender, ij'-2o' 

 high, woolly at the base and in the axils of the 

 lower leaves, or essentially glabrous. Basal leaves 

 slender-petioled, oblong, rarely slightly spatulate, 

 very obtuse, narrowed at the base, mostly thick, 

 crenate, or rarely dentate, often purplish, i'-s' 

 long, 3"-6" wide, their petioles and sometimes 

 their lower surfaces persistently tomentose or 

 woolly, or glabrous throughout ; lower stem leaves 

 petioled, laciniate or pinnatifid, the upper sessile, 

 very small ; heads few or several, slender-pedun- 

 cled, 6"-io" broad; involucre about 3" high; rays 

 8-12; achenes hispidulous or glabrous; pappus 

 white. 



In dry or rocky soil, Newfoundland to North Caro- 

 lina, Ontario, British Columbia, Alabama, Tennessee 

 and Nebraska. May-July. 



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