to the Rocky Mountains. 215 



disk purple, (yellow when first expanded ?) 5-cleft, the segments hairy. 

 Pappus 7-leaved, paleaceous, lanceolate and awned. Seed hairy. 

 Hab. On the Canadian ? 



232. RUDBECKIA COLUMNAKIS, Nutt. getl. H. p. 178. 



Sources of the Arkansa. 



233. R. fulgida. On the Missouri. Dr. Baldwin. 



234. Bidens gracilis, glaberrima ; foliis pinnato-quin- 

 quepartitis, laciniis angusto-linearibus, integerrimis ; caule 

 subramoso, erecto ; floribus terminalibus, solitariis, longe-pe- 

 dunculatis, discoiders ; bracteis inVolucro duplo brevioribus. 



Desc. Root perennial. Stem about two feet high, smooth, and some- 

 what glaucous, striate, divided above into several long naked branches, or 

 peduncles. Leaves opposite, petiolate, pinnately 5-parted, the divisions 

 entire, one line broad, very smooth. Flowers solitary, terminating the 

 branches, without rays. Involucrum smooth, rather shorter than the disk ; 

 leaflets oblong, obtuse. Bracts scarcely one-third the length of the invo- 

 lucrum, ovate, obtuse. Flowers yellow ? Seed with two awns. 



Hab. On the Canadian ? 



Obs. This species is nearly allied to B. angustifolia of 

 Kunth, which has tripartite leaves, with the segments cuspi- 

 date. 



235. Coreopsis crassifolia, Ait. Ell. sk. ii. p. 435. 

 C. lanceolata, /3. Michx.fl. ii. p. 137. On the Missouri, near 

 St. Louis. Dr. Baldwin. 



236. C. palmata, Nutt. gen. ii. p. ISO. 



237. Centaurea Americana, Nutt. in Bart. fl. amer. 

 sept. ii. t, 50. On the Canadian ; abundant. 



238. Helianthus altissimus, L. 7 Purshfl.'u. p. 471. 

 On the Platte. 



239. Silphium, n. sp. Nutt. mss. A singular species, 

 with pinnatifid leaves, and the scales of the involucrum very 

 narrow. Mr. Nuttall found the same on the Red River. 



240. S. TEREBINTHACEUM, Willd. sp. pi. \\\. p. 2331. 



On the Missouri. Radical leaves a foot and a half long, and 

 eight inches broad. 



Vol. II. 26 



