1304 CARDUACEAE 



9. Senecio rotiindus (Britton) Small. Perennial, glabrate. Stems 3-6 dm. tall, 

 corymbose above : leaves mainly basal ; blades suborbicular to orbicular-ovate, 3-7 cm. in 

 diameter, coarsely crenate-serrate, truncate at the base, decurrent into the margined peti- 

 oles, these as long as the blades or longer : heads in open corymbs : involucres 4-5 mm. 

 high ; bracts linear-subulate, 5 mm. long, acute : ligules of the ray-flowers light yellow, 

 linear, about 8-10 mm. long : achenes 2.5 mm. long. [.S'. obovatus rotundus Britton."] 



In low grounds or on wet rocks, Ohio to Missouri, Louisiana and Texas. Spring. 



10. Senecio obovatus Muhl. Perennial, nearly glabrous. Stems solitary or loosely 

 clustered, 1-5 dm. tall, corymbose above : leaves mainly basal or near the base of the stem ; 

 blades spatulate to obovate, 2-10 cm. long, rounded at the apex, coarsely toothed or ]:)artly 

 lyrate-pinnatifid, narrowed into broad petioles : stem-leaves with pinnatifid blades : heads 

 in open corymbs : involucres 4-5 mm. high ; bracts narrowly linear or subulate-linear : 

 ligules of the ray-flowers deep yellow, 5-7 mm. long : achenes 3-5 mm. long. 



In moist soil, Nova Scotia to Ontario, Michigan, Florida and North Carolina. Spring. 



11. Senecio Purshianus Nutt. Perennial, densely and persistently grayish white 

 tomentose to the involucres. Stems usually tufted, 1-2 dm. tall : leaves mostly crowded on 

 the caudex-like rootstocks, these mainly basal ; blades spatulate, 3-6 cm. long, entire, ob- 

 tuse, narrowed into slender petiole-like bases : heads solitary or few, showy : involucres 

 6-8 mm. high ; bracts narrowly linear, merely cobwebby in age : ligules of the ray-flowers 

 oblong or oval-oblong, 5-7 mm. long : achenes 3 ram. long, glabrous. 



In dry soil, Manitoba to British Columbia, Minnesota, Texas and Utah. Spring and summer. 



12. Senecio Balsdmitae Muhl. Perennial, densely and often permanently woolly 

 at the base of the stem and about its nodes. Stems solitary or tufted, 2-6 dm. tall, some- 

 times sparingly branched above : leaves mainly basal ; blades oblong to oblong-spatulate, 

 2-5 cm. long, toothed, sometimes with a few more salient teeth near the base ; petioles 

 commonly longer than the blades : stem-leaves 1-2-pinnatifid : heads in rather close cor- 

 ymbs : involucres 4-5 mm. high ; bracts narrowly linear, becoming glabrous : ligules of 

 the ray-flowers 4-5 mm. long : achenes about 2 mm. long, hispidulous. 



In stony or dry soil, Nova Scotia to British Columbia, North Carolina and Texas. Spring and 

 early summer. 



13. Senecio E^rlel Small. Perennial, bright green, densely cottony below, spar- 

 ingly so and glabrate above. Stems usually tufted, 2-5 dm. tall, corymbosely branched 

 above : leaves various, the basal quite numerous : blades oval or oblong, 1.5-6 cm. long, 

 serrate, obtuse or retuse, often crimson beneath ; petioles longer than the blades : stem- 

 leaves with pinnatifid linear-lanceolate or oblong blades, the upper sessile : peduncles 

 slender : involucres hemispheric, 8-9 ram. broad, 8-10 mm. high ; bracts linear or nearly 

 so, 5-5.5 mm. long, acute, hyaline-margined : rays oblong, 4-6 mm. long, bright yellow : 

 style glabrous : achenes 3 mm. long, scabro-pubescent on the angles. 



In dry soil, Tennessee and Alabama. Spring and summer. 



14. Senecio Sm^llli Britton. Perennial, woolly, permanently so below. Stems 

 usually tufted, 3-6 dm. tall, corymbose above : leaves mainly basal or near the base of the 

 stem ; blades narrowly oblong, linear-oblong or linear-lanceolate, 5-10 cm. long, finely 

 toothed or pinnatifid near the base, as long as the petioles or shorter ; stem leaves similar 

 to the basal or wholly pinnatifid, short-petioled or sessile : heads small, usually conspicu- 

 ous by their great number: involucres fully 6 mm. high ; bracts narrowly linear, acumi- 

 nate : receptacle about 3 mm. broad : ligules of the ray-flowers 4-6 mm. long : achenes 

 1.5-2 mm. long, hispidulous. 



In dry soil and meadows, Virginia to Tennessee, middle Georgia and Mississippi. Spring. 



15. Senecio Platt^nsis Nutt. Perennial, the stem and leaves persistently woolly. 

 Stems 2-4.5 dm. tall, corymbose above : leaves mainly basal ; blades oblong, ovate-oblong 

 or ovate, 2.5-4.5 cm. long, some or all of them pinnatifid or lyrate-pinnatifid, the terminal 

 segments toothed : heads showy : involucre 6.5-7.5 mm. high ; bracts linear, usually cob- 

 webby : ligules of the ray-flowers bright yellow, broadly oblong, 5-8 mm. long : achenes 2 

 mm. long. 



In dry soil, South Dakota and Wyoming to Illinois, Texas and Colorado. Spring. 



16. Senecio tomentosus Michx. Perennial, more or less densely pale tomentose. 

 Stems 2-7 dm. tall, corymbose above : leaves mainly basal ; blades oblong or oblong- 

 lanceolate, 3-15 cm. long, usually obtuse, crenate to nearly entire ; petioles longer than 

 the blades : stem-leaves few, rarely pinnatifid, the upper sessile and partly clasping : heads 

 at first clustered : involucres 7-8 mm. high ; bracts narrowly linear-lanceolate, acuminate; 

 becoming glabrous, or nearly so : ligules of the ray-flowers deep yellow, 7-9 mm. long : 

 achenes nearly 2.5 mm. long. 



In sandy soil, New Jersey to Florida, Arkansas and Texas. Spring. 



