84 COMPOSITAE. 



not united at the base, of copious capillary bristles, in tbe stanoinate flowers 

 not thickened above. 



A. margaritacea (L.) lienth. & Hook. Stem 1-2 feet high, simple,' eoryiu- 

 bosely branched above, leafy; leaves nearly linear to broadly lanceolate, acu- 

 minate, entire, sessile, becoming* green above, tbe larger obscurely 3-nerved; 

 involueral scales pearly-white, numerous, unequal, imbricated, obtuse. Fields 

 and open woods; July-August; frequent; Delaware, Johnson, and Deeatur 

 counties; perhaps generally distributed. This species is conf ustfd with the 

 following, the general appearance of which it resembles. 



GNAPrJALIUM L. Woolly or pubescent herbs, with sessile alternate 

 leaves, and variously clustered heads of fertile flowers. The pistillate flow- 

 ers in several series, the perfect flowers central, few. Pappus of capillary 

 bristles. 



G. polycephalum MS. Annual or winter-annual; stem 1-3 feet high, 

 woolly or tomentose; leaves lanceolate or linear-lafaeeolate, sessile, glabrate 

 above, white-Woolly beneath, margins undulate; heads in corymbose or pani- 

 culate clusters; pappus-bristles distinct. This species is frequently reported. 

 {G. obtusifiMiim L.) 



INULA' L. Coarse perennials, with alternate simple leaves, and large 

 many-flowered heads. ' Rays'pistillate, yellow. Disk flowers perfect, yellow. 

 Involucre hemispherical, of imbricated foliaceous scales. Receptacle naked. 

 Pappus simple, of capillary bristles. Anthers sagittate atthe base, the auri- 

 cles caudatel Acbenes somewhat 4 or 5-ribbed. 



I. Kelenium L. Elecampane. Stem 2-6 feet high, from a large thick root: 

 leaves large, oblong or ovate, woolly beneath,' entire or denticulate, radical 

 petioled, cauline clasping; scales ovate. Open woods; July-August; local; 

 Johnson county; rarely in waste 1 places. Deeatur county. 



POLYMNIA L». '■"■ Perennial branching herbs, with opposite or alternate 

 thin lobed leaves.and light yellow flower's. Heads radiate, many-flowered; 

 rays few, pistillate; disk flowers perfect but sterile. Involueral scales in two 

 rows; outer about 5," leaf-like, spreading;, inner smaller, membranaceous. 

 Receptacle flat, chaffy. Pappus Wanting. 



P. canadensis J Li; Stem 2-5'feet high, - clammy-hairy; leaves petioled, the 

 lower pihnatifid, the upper deltoid-ovate or hastate, 3-5-lobed or entire: rays 

 5, in the typical form shorter tharithe involucre, often minute or obortive: 

 achenes 3-ribbed. The form represented in our flora is variety kadiata 

 Gray, which has 1 the rays longer and 3-lobed. Wooded ravines; June-July; 

 frequent; Winneshiek, Allamakee, Clayton, Dubuque, Fayette, Muscatine, 

 and Des Moines counties^ 



SILPrJIUM L. Rosin-weed. Coarse perennials, with alternate or opposite 

 leaves, resinous juice; and large yellow-flowered heads. Ray-flowers many, 

 pistillate, fertile, in 2 or 3 rows, outer ligulate; disk-flowers perfect, sterile: 

 style entire. Involueral scales foliaceous, spreading, in several rows. Re- 

 ceptacle flat, chafFy. Pappus wanting or of 2 teeth. Achenes broad, flat, 

 dorsally compressed. 



* Stems terete; leaves alternate. 



S. lacin'iatum L. Compass-plant. Whole plant covered with whitish hairs; 

 stem 3-10 feet high, terete, simple; leaves alternate, pinnately parted; divi- 

 sions linear,' cut, sinuate-lobed or entire; petioles dilated at their bases; 

 radical or lower leaves 1-2 feet long; heads large, several, sessile or short 

 peduncled, mostly alternately arranged along the upper part of the naked 



