130 COMMON CANADIAN WILD PLANTS. 



41. BIDENS, L. BUR-MARIGOLD. 



1. B. frondo'sa, L. (COMMON BEGGAR-TICKS.) Rays none, 

 Achenes fiat, wedge-obovate, ciliate on the margins with 

 bristles, pointing upwards, 2-awned. Stem tall, branched. 

 Leaves thin, long-petioled, pinnately 3-5-divided, the leaf- 

 lets ovate-lanceolate, pointed, serrate. 



2. B. eonna'ta, Muhl. (SWAMP BEGGAR-TICKS.) Hays 

 none. Achenes flat, narrowly wedge-shaped, 2-4-awned, 

 ciliate with minute bristles, pointing downwards. Stem 1-2 

 feet high, smooth. Leaves lanceolate, pointed, serrate, 

 tapering and connate at the base, the lowest often 3-parted 

 and decurrent on the petiole. In shallow water and low 

 grounds. 



3. B. eer'nua, L. (SMALLER BUR-MARIGOLD.) Rays short, 

 pale yellow. Achenes flat, wedge-obovate, 4-awned, ciliate 

 with bristles pointing downwards. Stem nearly smooth, 

 5-10 inches high. Leaves all simple, lanceolate, unequally 

 serrate, hardly connate. Heads nodding. Wet places. 



4. B. ehrysanthemoi'des, Michx. (LARGE BUR-MARI- 

 GOLD.) Rays an inch long, showy, golden yellow. Achenes 

 wedge-shaped, 2 4-awned, bristly downwards. Stem smooth, 

 6-30 inches high, erect or ascending. Leaves lanceolate, 

 tapering at both ends, connate, regularly serrate. Swamps 

 and ditches. 



5. B. Beek'ii, Torr. ("WATER MARIGOLD.) Aquatic. Stems 

 long and slender. Immersed leaves dissected into fine hair- 

 like divisions ; those out of water lanceolate, slightly con- 

 nate, toothed. Bays showy, golden yellow, larger than the 

 involucre. Achenes linear, bearing 4-6 very long awns barbed 

 towards the apex. Ponds and slow streams. 



42. HELIOP'SIS, Pers. Ox-EYE. 



1. H. Isevis, Pers. Stem smooth, slender, branching. 

 Leaves ovate-lanceolate, acute, sharply serrate, on slender 

 petioles. Heads showy ; peduncles elongated. Dry open 

 thickets ; London and westward. 



