53 



COMI'OMTAK. 



Vol. III. 



i. Synosma suaveolens (L.) Raf. Sweet-scented Indian Plantain. Fig. 4609. 



Cacalia suaveolens L. Sp. PI. 835 



1753. 



Senecio suaveolens Ell. Bot. S. C. & Ga. 2: 



Synosma suaveolens Raf. ; Loud. Gard. 

 1832. 



328. 1821-24. 

 Mag. 8: 247. 



Glabrous or very nearly so throughout; stem stri- 

 ate, 3-5 high, leafy to the inflorescence. Leaves 

 triangular-lanceolate or hastate, sharply and irregu- 

 larly serrate, acuminate, 4'-lo' long, 2'-6' wide at 

 the base, the auricles sometimes with 1 or 2 lobes 

 on the lower side; petioles margined, or those of 

 the basal leaves naked and slender; uppermost leaves 

 sometimes merely lanceolate and sessile ; heads 2"-3" 

 broad in a usually large and compound corymb; in- 

 volucre 4"-6" high, its principal bracts linear, acute ; 

 heads 20-30-flowered. 



In woods, Rhode Island to Pennsylvania, New Jersey, 

 Illinois, Minnesota, Florida. West Virginia and Ken- 

 tucky. Called also wild caraway. Aug.-Oct. 



102. SENECIO [Tourn.] L. Sp. PI. 866. 1753. 



Annual or perennial herbs (some tropical species shrubby or even arborescent), with 

 alternate or basal leaves, and solitary corymbose or paniculate many-flowered heads, of both 

 tubular and radiate, or only tubular flowers, in our species yellow. Involucre cylindric or 

 campanulate, its principal bracts in 1 series, distinct, or united at the base, usually with some 

 shorter outer ones. Receptacle flat or slightly convex, mostly naked, often honeycombed. 

 Rays, when present, pistillate, fertile. Disk-flowers perfect, fertile, their corollas tubular, 

 the limb 5-toothed or 5-lobed. Anthers obtuse and entire at the base, or rarely slightly sagit- 

 tate. Style-branches of the disk-flowers usually recurving or spreading. Achenes terete, 

 or those of the marginal flowers somewhat compressed, 5-10-ribbed, papillose or canescent, 

 at least after wetting, and then usually emitting a pair of spiral threads. Pappus of numerous 

 slender or capillary, smooth or rough, mostly white bristles. [Latin, senex, an old man, 

 referring to the hoary character of some species, or to the white pappus.] 



An immense genus of probably at least 1200 species, of very wide geographic distribution. In 

 addition to the following, many others occur in the southern and western parts of North America. 

 Our species known as Groundsel, Ragwort, or Squaw-weed. Type species : Senecio vulgaris L. 



A. Annual or biennial species, with stems leafy throughout. 

 Rays none, or very short and inconspicuous ; introduced. 



The short outer involucral bracts black-tipped; rays none. 1. S. vulgaris. 



Tin- short outer involucral bracts not black-tipped, sometimes none; rays very short. 



Plant sparingly pubescent. 2. -S". sylvaticus. 



Plant densely viscid-pubescent. 3. 5. viscosus. 



Rays large and conspicuous : native species. 



Leaves pinnately divided ; heads 2" 3" high. 

 Leaves sinuate-dentate or the lower entire ; heads 4" 



B. Perennial species, mostly with rootstocks. 

 a. Stems woody at base; leaves linear, or pinnatifid with linear lobes; western species. 

 Leaves linear, entire or serrate, thin. 6. S. spartioides. 



Leaves deeply pinnatifid into linear lobes, firm. 7. .S. Riddellii. 



b. Stems wholly herbaceous ; leaves various. 

 * Heads very large; involucre 7"-io" high; boreal species. 



Stem stout, leafy above; heads several, iJ^'-2' broad. 8. S. Pseudo-Arnica. 



Stem slender; upper leaves few and small ; head mostly solitary, about 1' broad. 9. S.frigidus. 



** Heads smaller: involucre 4"-7" high. 



t Leafy up to the inflorescence ; stem leaves 2-3-pinnatifid ; introduced species. 



10. 5". Jacobaea. 

 tt Leaves mostly borne on the lower part of the stem, the upper ones much smaller ; native species. 



t Leaves and stems more or less persistently woolly or tomentose. 

 Low species, seldom over 1 high, with small oval-oblong to spatulate basal leaves. 



Basal leaves angulate-dentate, oval. n. S. antennariifolius. 



Basal leaves entire or sparingly toothed, oblong to spatulate. 12. 5. canus. 



high. 



4. 5". glabellas. 



5. S. paluslris. 



