CARDUACEAE 1303 



Primary leaf-divisions 1-2-pinnatifid. 18. S. Memmingeri. 



Primary leaf-divisions dissected, the ultimate divisions mainly 



linear. 19. S. Mittefolium. 



B. Plants woody : leaf-blades pinnately parted into 3-9 linear or filiform- 

 linear segments. 20. S. Fremontii. 



1. Senecio Rug61ia A. Gray. Perennial, villous-hirsute. Stems 2-5 dm. tall, some- 

 times sparingly branched above : leaves mainly basal ; blades ovate to oblong-oval, 8-15 

 cm. long, acute, denticulate or dentate, abruptly narrowed or subcordate at the base ; peti- 

 oles commonly longer than the blades, margined, the stem leaves usually with smaller 

 blades and shorter petioles : heads long-peduncled : involucres over 1 cm. high ; bracts 

 about 12, linear-lanceolate, the larger 12 mm. long, glabrous or nearly so : achenes slen- 

 der, 6 mm. long. 



In thickets at very high altitudes, North Carolina and Tennessee. Summer. 



2. Senecio Mississippianus DC. Annual and similar to 8. lobatus in habit. Stem 

 1.5-5 dm. tall, usually simple below the inflorescence : leaf-blades 4-9 cm. long, pinnately 

 parted or divided, the segments few-lobed, the terminal lobe reniform, flat at the apex and 

 3-5-lobed : heads few or several, conspicuous : involucres 4-5 mm. high ; bracts acumi- 

 nate : ligules of the ray-flowers oblong to oblong-spatulate, 3.5-5 mm. long : achenes 1.5 

 mm. long, hispidulous. 



In low grounds, Arkansas and the Indian Territory to Louisiana and Texas. Spring and summer. 



3. Senecio lobatus Pers. Annual or biennial, succulent, thinly woolly, or gla- 

 brous at maturity. Stems 1-9 dm. tall, hollow, more or less branched above : leaf-blades 

 3-20 cm. long, pinnately parted or divided, the segments cuneate to suborbicular, coarsely 

 toothed : heads showy : involucres less than 6 mm. high ; bracts linear, acute, 5-6 mm. 

 long : ray-flowers 6-12 : ligules yellow, linear or linear-oblong, 5-8 mm. long : achenes 1.5 

 mm. long, hispidulous on some of the angles. 



In wet soil and river bottoms, Illinois and Missouri to North Carolina, Florida, Texas and Mexico. 

 Spring to fall. 



4. Senecio Greggii Eydb. Annual or biennial, bright green. Stems branched at 

 the base, the branches several together and tufted, 1.5-3 dm. tall, somewhat scape-like : 

 leaf-blades 2-7 cm. long, pinnately divided, except the few very early ones, the segments 

 mainly obovate, each shallowly few-lobed : heads showy, in a compound cyme : involucres 

 4-5 mm. high ; bracts linear, acuminate : ligules of the ray-flowers 3-4 mm. long : achenes 

 hispidulous, nearly 2 mm. long. 



In low grounds, Texas and Mexico. Spring and summer. 



5. Senecio ampullaceus Hook. Annual or biennial, woolly when young, smooth 

 and glabrous in age. Stems 2-6 dm. tall, corymbose above : leaf-blades oblong, oval or 

 oblong-lanceolate, 5-15 cm. long, entire or denticulate, the lower ones contracted into 

 petiole-like bases, the upper ones sessile : heads showy, often numerous : involucres over 6 

 mm. high ; bracts narrowly linear, 7-10 mm. long : ligules of the ray-flowers yellow, 9-15 

 mm. long : achenes 4 mm. long, scabrous, contracted under the top. 



On sandy prairies, Texas. Spring and summer. 



6. Senecio Robbinsii Cakes. Perennial, glabrous or nearly so. Stems often tufted, 

 3-10 dm. tall, corymbose above : leaf-blades thinnish, those of the basal leaves lanceolate 

 or oblong-lanceolate, 3-8 cm. long, acute, serrate or incised-serrate, subcordate or truncate 

 at the base ; petioles often several times longer than the blades : stem-leaves mostly dilated, 

 incised, partly clasping by stipule-like bases : involucres glabrous ; bracts linear-subulate, 

 5-6 mm. long, acute : ligules of the ray -flowers linear, 4-5 mm. long : achenes nearly 3 

 mm. long, sharply ribbed. 



In mountain meadows, New Hampshire and Vermont to New York and on Roan Mountain, North 

 Carolina and Tennessee. Summer. 



7. Senecio aureus L. Perennial, glabrous at least below the inflorescence. Stems 

 solitary or clustered, 3-7 dm. tall, corymbose above : leaf-blades of the basal leaves ovate, 

 oval or suborbicular, 2-12 cm. long, rounded at the apex, crenate or serrate-crenate, cor- 

 date ; petioles longer than the blades : stem-leaves with pinnatifid or lyrate-pinnatifid 

 blades, the segments often cuneate, sometimes toothed : heads showy, slender-ped uncled : 

 involucres 6-7 mm. high ; bracts linear, fully 1 mm. broad : ligules of the ray-flowers 

 linear or linear-oblong, deep yellow, 5.5-7.5 mm. long : achenes 3 mm. long. 



In swamps and meadows, Newfoundland to Ontario, Missouri, Florida and Texas. Spring and 

 summer. 



8. Senecio gracilis Pursh. Similar to S. ^aureus in habit but smaller and more 

 slender : heads few, about one-half as large as those of S. aureus: involucres 3.5-4.5 mm. 

 high : ligules of the ray-flowers broadly oblong or oval, 3.5-5 mm. long. 



In wet grounds, Pennsylvania to Georgia. Spring. 



