152 GAMOPETALOUS EXOGENS 



angled and dentate, upper ones rhomboid and cuneate, coarsely 

 dentate ; heads about 5-flowered. 

 ATRIPLEX-LEAVED CACALIA. Indian Plantain. 



Stem, 3 to 5 or 6 feet high, striate, often purplish, but glaucous withal. Leaves, 

 conspicuously nerved, pale or yellowish green above, glaucous beneath, the radi- 

 cal ones 4 to 6 inches in length, and about as wide as long, on striate petioles 3 to 6 

 or 8 inches long, stem-leaves gradually smaller, the uppermost often oblong and 

 entire, and the petioles gradually shorter. Heads of flowers small, numerous. 

 Receptacle with an acute membranous column in the centre, longer than the 

 akenes, and apparently formed of connate chaffy scales. 

 Hob. "Woodlands, and moist shaded grounds : frequent. Fl. July. Fr. Sept. 



218. SEIVE V CIO, L. 



[Latin, Senex, an old man ; the pappus resembling a white beard.] 

 Heads many-flowered, either discoid with the florets all perfect, or 

 radiate with the ray-florets pistillate. Involucre subcylindric ; 

 scales in a single series, or with bractlets at base. Akenes oblong, 

 ribbed; pappus of numerous soft slender hairs. Receptacle flat, 

 naked. Heads mostly corymbed ; florets chiefly yellow. 



f Heads discoid : Annuals. 



1. S. vulgaris, L. Leaves pinnatifid and dentate, the lowest petio- 

 late, the upper clasping ; heads nodding. 

 COMMON SENECIO. Groundsel. 



Stem 6 to 12 or 15 inches high, paniculately branching, angular, mostly smooth- 

 ish. Leaves 1 to 3 inches long, the upper ones somewhat auricled and clasping, 

 the lower ones on petioles % an inch to an inch in length. Involucre somewhat 

 conical, smooth ; scales often sphacelate, or blackish, at apex, bracteolate at base. 

 Akenes pubescent on the ribs. 

 Hob. West-Chester. Nat. of Europe. Fl. July, Fr. Sept. 



Obs. This homely little weed was detected in the streets of West 

 Chester, in 1846, by Mr. PENNOCK PASSMORE; and in 1850 was ex- 

 ceedingly multiplied in the same locality, though scarcely to be 

 seen, the succeeding year. Prof. DE CANDOLLE says it has migrated 

 almost every where, with European men; but whether it is likely to 

 become troublesome to our farmers, is not yet ascertained. 



f f Heads radiate : Perennials. 



*. S. Siureu$ ? L. Radical leaves roundish-cordate, obovate, or 

 lance-oblong, stem-leaves lyrate, ox lanceolate and pinnatifid; 

 corymb umbel-like. 



AUo, S. obovatus, and Balsamitae. Muhl. $ Fl. Cestr. ed. 2. p. 497. 

 GOLDEN SENECIO. Rag-wort. Squaw-weed. 



Stem 1 to 2 feet high, striate, smoothish, or floccose-woolly when young. Radi- 

 cal leaves 1 to 3 inches long, varying from cordate to obovate, and lanceolate ; petio- 

 les 1 or 2 to 6 or 8 inches long ; stem-leaves sessile and often clasping. Heads of 

 flowers on peduncle-like subumbellate branches. 

 Hob. Banks of streams, and moist grounds : frequent. Fl. May. Fr. July. 



Obs. TORREY and GRAY have reduced two of MUHLENBERG'S 

 species (along with 2 or 3 others) to the grade of varieties ; which 

 may be well enough, whenever practicable, in a genus that com- 

 prises near 600 species. 



