1478 CARDUACEAE 
192. SENECIO [Tourn.] L. Annual or perennial herbs. Leaves alter- 
nate: blades entire, toothed, pinnatifid, or pinnately par rted. Heads solitary 
or many. Involuere campanulate to cylindric: bracts flat. Ligules of the 
ray yellow, when present, in our species. Disk-corollas yellow with a funnel- 
form throat and triangular or ovate lobes. Filaments often enlarged below 
the anthers. Achene 5-10-ribbed, pubescent or papillose.—A bout 1,500 species, 
widely distributed.—Spr.—SqUAW-WEEDS. RAGWORTS. RAGWEEDS. GROUNDSELS. 
Plant annual or perhaps biennial: pubescence, if present, arachnoid. 
Ray-flowers Dos achene pubescent on B age S. I. LOBATI. 
Ray-flowers wanting : achene pubescent all o II. VULGARES. 
Plant perennia al: foliage, if pubescent, woolly Ur E l 
H large, the involucres over 1 cm. high: ray- Towers 
non io III. NUDICAULES, 
po small, the Du cien less than 1 em. high: ray- 
owers normally present. 
Mn of the basal jede es toothed or partly and slightly 
lyrate-pinnati IV. AUREI. 
Blades of the basal leaves pinnately parted and twice 
irice pinnatifid or dissected. V. MILLEFOLIA. 
I. LOBATI 
Plant with pinnately parted leaf-blades: involuere 4—5 mm. 
hi 
gh; bracts light-green. 1. S. glabellus. 
VULGARE 
Plant with pinnatifid leaf-blades: soluere 6-8 mm. high; 
2E acts, as well as the small bracts at then Ted dark-green 
r black. 2. S. vulgaris. 
NUDICAULES 
Stem usually bearing 3-5 pedunculite somewhat racemose 
heads: heads very many-flowered. 3. S. Rugelia. 
T 
I AURIE 
Blades of the pasa leaves cordate or truncate at the base. 
Blades of t basal leaves p one lanceolate or 
sllipiic lanceolate, sharply serr 4. S. Robbinsit. 
of the basal leaves 
volucres over 5 i high. 
olucres less T D ma 
aureus. 
high. ili 
Blades Jus asal fuc gradually narrowed or cuneate at 
gracilis. 
di 
un 
Biades of the basal leaves scarcely longer than broad. 7. S. rotundus. 
Blades of the basal leaves manifestly or markedly longer 
han broad. 
Blades of the basal leaves wholly, or predominately, 
narrowly or broadly spatulate: achene glabrous. 8. S. obovatus. 
Blades of the basal plene wholy, or predominately 
elliptic, oval, Ad per ceolate : àchene pubescent. 
copiou 
n 
densely SN Mo base of the stem and petioles ot 
the basal leaves usually T silky-tomen 
ose. 
Involucre 4-6 mm. high: blades of the basal 
leaves elliptic or oval, varying to broadest 
above or below the middle, or oblanceolate 
to lanceolate. 
Blades of the basal leaves elliptic to oval, 
y to ovate or obovate: involucre 5—6 
9. S. pauperculus. 
10. S. Smallii. 
Blades of "the basal ed irse lanceolate 
to oblanceolate: involu 5 mm. long. 
m 6—7 mm. high: blades of the basal leaves 
triangular- mud to broadly lanceolate, triangu- 
lar-lanceolate, or ovate. 1. S. tomentosus. 
deed nearly Sino. "^ the base of the stem, petioles, 
inflorescence inconspicuously arachno id. 19. S. alabamensis. 
V. MILLEFOLIA 
Primary leaf-divisions 1—2-pinnatifid. 13. S. Memmingeri. 
Primary leaf-divisions dissected, the ultimate divisions mainly 
linear. 14. S. Millefolium. 
