Gen IS 92.] 



THISTLE FAMILY. 



473 



I. Erechtites hieracifolia 



(L.)Raf. Fire-weed. Pilewort. 



(Fig. 4028.) 



Senecio hieracifoHus L. Sp. PI. 866. 



1753- 

 Ereclilttes hieracifolia Raf. DC. Prodr. 

 6: 294. 1837. 



Annual, glabrous, or somewhat hir- 

 sute; stem striate, succulent, usually 

 branched, i°-8° high. Leaves thin, 

 lanceolate or ovate-lanceolate, den- 

 tate and often deeply incised, 2'-S' 

 long, the upper sessile or auriculate- 

 clasping, mostly acuminate, the lower 

 usually narrowed into petioles; heads 

 6"-io" long, about 3" in diameter, 

 the involucre conspicuously swollen 

 at the base before flowering, its bracts 

 numerous, striate, green, with narrow 

 scarious margins ; pappus bright white. 



In woodlands, thickets and waste 

 places, very abundant after fires, New- 

 foundland to Florida, west lo the North- 

 west Territory, Nebraska and Louisiana. 

 Also in Mexico and South America. 

 July-Sept. 



93. MESADENIA Raf.; I,oud. Gard. Mag. 8: 247. 1832. 



Tall perennial mostly glabrous herbs, with alternate petioled leaves and numerous, 

 rather small, corymbose, discoid heads of white, yellowish or pinkish flowers, all tubular and 

 perfect. Sap milky (at least in some species). Involucre cylindric or nearly so, its princi- 

 pal bracts 5, in i series, equal, usually with a few short outer ones. Receptacle flat, not 

 chaffy, with a fleshy projection in the centre. Corollas with somewhat spreading 5-cleft limbs, 

 the lobes usually with a mid-nerve. Style-branches conic or obtuse at the apex, .\chenes 

 oblong, glabrous. Pappus of copious white scabrous bristles. [Greek, referring to the cen- 

 tral projection of the receptacle.] 



.\bout 12 species, natives of North and Central ."Vmerica. Besides the following, 4 others occur 

 in the southern and southwestern parts of the United States. 

 Leaves thin, reniform or fan-shaped, lobed, or angulate-dentate. 



Leaves green both sides, angulate-dentate. i. M. reniformis. 



Leaves glaucous beneath, green above, angulate-lobed. 2. Af. atriplicifolia.^ 



Leaves thick, green both sides, ovate or oval, entire, or repand. 3. M. liiberosa. 



I. Mesadenia reniformis (Miihl.) 



Raf. Great Indian Plantain. Wild 



Collard. (Fig. 4029.) 



Cacalia reniformis Muhl. ; Willd. Sp. PI. 3: 



1735. 1804. 

 Mesadenia reniformis Raf.New FI.4 : 79. 1836. 



Glabrous; stem angled and grooved, 4°- 

 10° high. Leaves thin, green both sides, 

 coarsely angulate-dentate with mucronate- 

 pointed teeth, the basal and lower reniform, 

 long-petioled, sometimes 2° wide, the upper 

 ovate or fan-shaped, mostly cuneate at the 

 base, the uppermost small and oblong; 

 heads numerous, mostly 5-flowered, about 

 1" broad, in large compound corymbs; in- 

 volucre 3"-4" high, its bracts about 5, lin- 

 ear-oblong, obtuse or acutish, scarious-mar- 

 giued, with or witliout 1-3 minute outer 

 ones. 



In woods, New Jersey and Pennsylvania 

 to Minnesota, south to North Carolina and 

 Tennessee. July-Sept. 



