cojiPOsiT.E. (composite family.) 215 



often pedicclled, top-shaped; rays about 10. — Low sandy places, common. 

 Oct. — Stem 2° high. Heads smaller than those of the preceding. 



21. BIGELOVIA, DC. 



Heads 3-4-flowered; the flowers all tubular and perfect. Involucre cylin- 

 drical-club-shaped, as long as the flowers ; the scales linear, rigid, appressed, 

 somewhat viscid. Receptacle narrow, cuspidate. Achenia terete, striate, hairy. 

 Pappus simple, of numerous scabrous capillary bristles. Styles scarcely exserted. 

 — A smooth erect perennial herb, with narrow obtuse and entire leaves, and small 

 heads of yellow flowers, disposed in a compound corymb. 



1. B. nudata, DC. Stem mostly simple, virgate; lowest leaves spatu late- 

 lanceolate, obscurely 3-nerved ; the others scattered, linear. (Chrysocoma nu- 

 data, Michx.) — Var. viRGATA. Lowest leaves linear-spatulate, 1-nerved; the 

 others narrow-linear or filiform ; heads larger. — Low pine barrens, Florida, and 

 northward. Sept. — Stem 2° high. 



22. ISOPAPPUS, Torr. & Gray. 



Heads several-flowered. Rays 5-12, pistillate. Involucre cylindrical-cam- 

 panulate ; the scales lanceolate-subulate, imbricated in 2-3 rows, appressed. 

 Receptacle alveolate. Achenia terete, silky. Pappus a single row of nearly 

 equal capillary bristles. — Biennials. Stems paniculate. Leaves alternate, nar- 

 r. Heads scattered, on slender peduncles. Rays yellow. 



1. I. divai'ieatus, Torr. & Gray. Hispid and glandular ; stem erect, the 

 slender branches spreading; leaves linear-lanceolate, sparingly toothed ; involu- 

 cre soft-hairy; rays 5-8. (Chrysopsis divaricata, Nutt.) — Sandy fields and 

 woods, Florida, Georgia, and westward. Sept. — Stem l°-4° high. Panicle 

 large. Heads 15-20-flowered. 



23. HETEROTHECA, Cass. 



Heads many-flowered. Rays pistillate. Scales of the involucre imbricated in 

 few rows, linear. Receptacle alveolate, bristly. Achenia of the rays oval, des- 

 titute of pappus, those of the disk-flowers obovate, compressed, haiiy, with a 

 double pappus ; the outer one short and chaff'y, the inner bristly. — Biennial 

 rough-hairy branching herbs, with irregularly toothed or entire alternate leaves, 

 and corymbose-pan icled heads of yellow flowers. 



1. H. SCabra, DC. Leaves oblong, toothed, commonly sessile or clasp- 

 ing ; the lowest jictioled, obtuse or somewhat cordate at the base; involucre 

 thick, shorter than the brownish inner pappus. (Chrysopsis scabra, jVk?/.) — 

 Dry sandy places along the coast, South Carolina, and westward. Sept. — Stem 

 rigid, 10-2° high. Leaves 1 ' - 2' long. 



24. CHRYSOPSIS, Nutt. 



Pappus of the ray and disk-flowers alike, double ; the e.xterior row chaflfy, or 

 of chaffy bristles, the interior longer, capillary ; otherwise like Heterothcca. — 



