CAKDUACEAE 1301 



2. Mesadenia sfmilis Small. Similar to M. atriplicifolia in habit. Stem relatively 

 stout, furrowed, corymbosely branched above : leaf-blades green above, glaucous beneath, 

 those of the basal and lower stem-leaves much larger than those of the upper, undulate- 

 sinuate, deeply cordate, long-petioled : heads rather smaller than those of M. atriplicifolia. 



On prairies and in low grounds, Arkansas. Summer. 



3. Mesadenia atriplicifolia ( L. ) Raf. Stems 1-2 m. tall, glabrous, terete : leaf- 

 blades various, those of the basal leaves orbicular-reniform or broadly ovate, 10-15 cm. 

 broad, those of the stem-leaves smaller, ovate or triangular, or narrower above, all angu- 

 lately 3-7-lobed or coarsely and sharply toothed, cordate to cuneate at the base, all glaucous 

 beneath : heads numerous : involucral bracts linear, oblong-linear, oblong-lanceolate, 8-11 

 mm. long, wingless : achenes 4-4.5 mm. long.. 



In open woods and thickets, Ontario to Minnesota, Florida and Kansas. Summer and fall. 



4. Mesadenia maxima Harper. Stem about 1.5 m. tall, terete, glaucous: leaf- 

 blades thickish, those of the lower leaves about 25 cm. long and 20 cm. broad, truncate at 

 the base, long-petioled, those of the upper gradually reduced in size and proportionately 

 narrower, all glaucous on both sides, very coarsely sinuate-toothed, more or less digitately 

 veined, the veins forking and often anastomosing : heads in a terminal compound corymb 

 5-6 dm. long and nearly as broad : involucral bracts bright green, about 1 cm. long, wing- 

 less. 



In dry pine lands, Sumter County, Georgia. Summer. 



5. Mesadenia ovata (Walt.) Kaf. Stems 8-12 dm. tall, terete: leaf-blades thin- 

 nish, ovate to oval, 8-20 cm. long, entire or repand-undulate, truncate and cuneate and 

 palmately nerved at the base ; petioles of the basal and lower stem-leaves as long as the 

 blades : heads often numerous : involucral bracts narrowly oblong or linear-lanceolate, 8-10 

 mm. long : corollas with very little throat. 



In damp woods or swamps, Georgia and Florida to Louisiana. 



6. Mesadenia lanceolata (Nutt.) Raf. Stems 8-15 dm. tall, terete : leaf -blades 

 linear, narrowly lanceolate or linear-oblong, 5-30 cm. long, entire or repand-denticulate ; 

 petioles margined, the lower ones longer than the blades : heads relatively few : involucral 

 bracts linear or narrowly oblong-lanceolate, 8-10 mm. long : achenes about 5 mm. long. 



In wet pine lands, Georgia and Florida to Louisiana. Spring to fall. 



7. Mesadenia diversifolia (T. & G.) Greene. Similar to M. atriplicifolia in habit, 

 but not glaucous : corolla-lobes but little longer than the throat. Little known. 



In swamps, South Carolina to Florida. Summer. 



8. Mesadenia difformis Small. Stems 7-11 dm. tall, terete : leaf-blades various, 

 those of the lower cauline leaves ovate, some of them narrowly ovate, undulate or merely 

 sinuate, 2-4.5 cm. long, obtuse, on greatly elongated petioles, those of the upper cauline 

 leaves ovate in outline but hastate and sharply dentate or dentate-lobed, 2.5-4 cm. long, even 

 the uppermost one like the others nearly truncately narrowed into petiole-like bases : heads 

 few in the terminal corymb : involucral bracts winged. 



In swamps, western Florida. Summer. 



9. Mesadenia tuberosa ( Nutt. ) Britton. Stems 6-1 2 dm. tall, sulcate or angled : leaf- 

 blades thickish, ovate, oval, oblong-lanceolate or narrowly elliptic, 5-20 cm. long, 5-9- 

 nerved, entire, denticulate or repand-dentate, attenuate or truncate at the base ; petioles 

 margined, those of the basal and lower stem-leaves as long as the blades or much longer : 

 involucral bracts narrowly oblong, winged, 8-10 mm. long: achenes 4.5-5 mm. long, 

 granular, ribbed. 



>On damp prairies, Ontario to Minnesota, Alabama and Louisiana. Summer. 



10. Mesadenia Floridana (A. Gray) Greene. Stems 7-12 dm. tall, channeled: leaf- 

 blades thickish, ovate, oval or oblong, 5-15 cm. long, coarsely crenate or crenate-dentate, 

 cuneately constricted at the base, the upper ones sessile or nearly so : heads numerous : invo- 

 lucral bracts oblong or nearly so, 10-12 mm. long, winged : corollas with lobes slightly longer 

 than the throat : achenes about 5 mm. long. 



In low pine lands, Florida. Spring and summer. 



11. Mesadenia sulcata ( Fernald ) Small. Stem 1-1.5 m. tall, deeply channeled: 

 leaf-blades ovate to oblong-ovate, narrowly elliptic or oblong-lanceolate, 8-20 cm. long, or 

 shorter toward the inflorescence, those of the basal and lower cauline leaves sinuate-dentate, 

 narrowed into long petioles, the upper closely sessile, usually sharply and deeply toothed : 

 heads numerous : involucral bracts oblong or oblong-lanceolate, 8-10 mm. long, winged. 



In sandy bogs or wet woods, southern Georgia and northern Florida. Summer and fall. 



