GENUS 100. 



THISTLE FAMILY. 



537 



2. Mesadenia atriplicifolia (L.) Raf. Pale Indian Plantain. Fig. 4607. 



Cacalia atriplicifolia L. Sp. PI. 835. 1753. 



Senecio atriplicifolius Hook. Fl. Bor. Am. I : 

 332. 1833. 



Mesadenia atriplicifolia Raf. New Fl. 4 : 79. 

 1836. 



Stem terete, glabrous and glaucous, 

 3-6 high. Leaves thin, angulate-lobed, 

 palmately veined, glaucous beneath, the 

 lower and basal ones slender-petioled, 

 sometimes 6' wide, the upper reniform, 

 fan-shaped, or triangular with a nearly 

 truncate base, the uppermost commonly 

 small, lanceolate or oblong and entire ; 

 heads very numerous, about \\" broad, 

 in large, loose compound corymbs ; invo- 

 lucre 3"-4" high, its bracts linear-oblong, 

 scarious-margined, with or without 1-3 

 minute outer ones. 



In woods, New Jersey to Indiana, Minne- 

 sota, south to Florida, Tennessee, Missouri 

 and Kansas. Recorded from Ontario. Called 

 also wild caraway. July-Sept. 



3. Mesadenia tuberosa (Nutt.) Britton. 

 Tuberous Indian Plantain. Fig. 4608. 



Cacalia tuberosa Nutt. Gen. 2: 138. 1818. 

 Mesadenia plantaginea Raf. New Fl. 4: 79. 1836. 

 Senecio Nuttallii Sch. Bip. Flora 27: 499. 1845. 

 M. tuberosa Britton in Britt. & Brown, 111. Fl. 3 : 

 474. 1898. 



Glabrous and green throughout; stem angled, 

 stout, 2-6 high. Leaves thick, strongly 5-9- 

 nerved, the lower and basal ones oval, ovate, 

 or ovate-lanceolate, obtuse or acutish, usually 

 quite entire, but sometimes repand, long-peti- 

 oled, narrowed at the base, or rarely subcordate, 

 4'-8' long, i '-3' wide; upper leaves ovate to 

 oblong or cuneate-obovate, sessile or short-peti- 

 oled, much smaller, sometimes toothed toward 

 the apex ; heads very numerous in a compound 

 corymb, about 2" broad, mostly 5-flowered ; 

 involucre 3"-4" high, its bracts linear-oblong, 

 obtuse or obtusish, scarious-margined. 



On wet prairies and in marshes, Ohio and west- 

 ern Ontario to Minnesota, Kansas, Alabama, Louisi- 

 ana and Texas. June-Aug. 



101. SYNOSMA Raf.; Loud. Card. Mag. 8: 247. 1832. 



A perennial leafy herb, glabrous or very nearly so, with triangular or hastate, alternate 

 leaves, the lower petioled, the upper sessile, and several or numerous, corymbose or corym- 

 bose-paniculate, discoid heads of white or pinkish flowers. Involucre nearly cylindric, its 

 principal bracts 12-15, linear, acute, usually with some subulate outer ones. Receptacle flat, 

 naked. Flowers perfect ; corolla 5-lobed. Style-branches not appendaged. Pappus of very 

 numerous white soft capillary bristles. [Greek, perhaps signifying a fragrant composite.] 



A monotypic genus of eastern North America. 



