1300 CARDUACEAE 



equal, in one or two series. Receptacle flat, naked, fimbrillate or pubescent. Ray-flowers 

 pistillate, fruit-producing : ligules yellow. Disk-flowers perfect, fruit-producing : corollas 

 tubular. Anthers sometimes slightly sagittate. Achenes narrow, more or less pubescent, 

 5-10-ribbed. Pappus a single series of scabrous or barbellate Arm bristles. 



1. Arnica acaulis ( Walt. ) B.S. P. Foliage hirsute. Stems 2-10 dm. tall, simple 

 or sparingly branched above, commonly bearing 1 or 2 pairs of leaves with nearly oblong 

 blades : leaves mainly basal ; blades spreading on the ground, oblong to oval or ovate, 5- 

 12 cm. long, shallowly toothed or nearly entire, sessile : heads showy, long-peduncled : 

 involucral bracts linear or linear-lanceolate, about 1 cm. long, acute : ligules of the ray- 

 flowers deep yellow, 1.5-2.5 cm. long : achenes 4 mm. long. [^4. nudicaulis Nutt. ] 



In pine lands and open woods, Pennsylvania to Florida. Spring. Leopard's-bane. 



139. ERECHTITES Raf. 

 Annual caulescent normally coarse herbs. Leaves alternate : blades flat, not rigid, 

 usually toothed or pinnatifid. Heads heterogamous, discoid, in corymbs or panicled 

 corymbs. Involucres narrow, somewhat swollen at the base : bracts mostly in 1 series, nar- 

 row, the main series sometimes accompanied by smaller ones. Receptacle flat or concave, 

 n^iked. Pistillate flowers marginal. Perfect flowers central, like the pistillate, fruit-pro- 

 ducing. Corollas tubular, white or greenish. Anthers obtuse at the base. Achenes nar- 

 row, angled or striate. Pappus copious, conspicuous, of soft white elongated bristles. 



1. Erechtites hieracifolia ( L. ) Raf. Foliage glabrous or sparingly hirsute. Stems 



2-20 dm. tall, simple or much branched : leaf-blades flimsy, spatulate-oblong or lanceolate, 



5-20 cm. long, acute or acuminate, coarsely toothed, incised or pinnatifld, the lower ones 



with winged petioles, the upper sessile and partly clasping : heads not showy : involucres 



cylindric, 12-15 mm. long ; bracts narrowly linear : achenes 1.5 mm. long, ribbed ; pappus 



bright white, silky. 



In open woods, and especially on burnt soil, Newfoundland to the Northwest Territory, Florida, 

 Louisiana and Mexico. Summer and fall. Fire-weed. 



140. MESADENIA Raf.' 

 Perennial herbs, with mostly glabrous foliage and sometimes a milky sap. Stems 

 corymbosely branched above. Leaves alternate : blades various, sometimes ample, undu- 

 late or toothed, commonly petioled. Heads often numerous, discoid, corymbose. In- 

 volucres cylindric or nearly so : bracts narrow, about 5 in 1 series, but commonly accom- 

 panied by a few small ones at the base of the involucre. Receptacle flat, with a fleshy 

 projection at the center, not chaffy. Corollas tubular, white, pinkish or yellowish : lobes 

 usually with a midnerve. Anthers not tailed at the base. Achenes narrow, 5-11-ribbed. 

 Pappus copious, of soft scabrous white bristles. Indian Plantain. 



Bracts of the involucre wingless. 



Corolla-lobes fully twice as long as;the throat. 



Leaf-blades pedately or digitately veined, those of the lower leaves broader than long. 

 Leaves green on both sides or glaucous beneath ; blades^pedately veined. 



Leaves green : stem furrowed. ' 1. M. reniformis. 



Leaves glaucous beneath. 



Stem furrowed. 2. M. similig. 



Stem terete. 3. 3/. atripUci/olia. 



Leaves glaucous on both sides :. blades digitately veined." 4. M. viaxima. 



Leaf-blades parallel-veined or subpinnately veined : stem terete. 



Leaf-blades ovate, commonly broadly so. 5. M. ovala. 



Leaf-blades linear to lanceolate. 6. M. lanceolata. 



Corolla-lobes but slightly longer than the throat. 7. M. diversifolia. 



Bracts of the involucre winged along the midrib. 



Stems terete, merely striate : blades of the upper stem-leaves hastate. 8. if. difformis. 



Stems channeled or angled : blades of the upper stem-leaves not hastate. 

 Lower leaves with 7-9-veined entire or crenatei blades. 



Leaf-blades entire or nearly so. 9. if. tuberosa. 



Leaf-blades crenate. 10. M. Floridana. 



Lower leaves with 3-5-veined sinuate-dentate blades. 11. il. sulcata. 



1. Mesadenia renifdnnis (Muhl.) Raf. Stems 1-3 m. tall, sometimes tomentulose 

 above, angled : leaf-blades ample, reniform, 1-6 dm. broad, repand or angulately lobed, 

 deeply cordate to cuneately truncate, green : heads often numerous : involucral bracts often 

 5, oblong to lanceolate, 8-11 mm. long : corollas with lobes fully twice as long as the 

 throat : achenes 5 mm. long, black. 



In rich woods. New Jersey to Minnesota, Georgia and Tennessee. Summer and fall. 



^ Prepared with the assistance of Mr. Roland M. Harper. 



