420 OYNANDRIA MONANDRIA. 



HAB. Rocky woods. Aug. Sept. QJ.; stem 3 i feet high; j 



middle-sized. 



1 1 Upper leaves alternate. 



H. giganteus : leaves alternate, lanceolate, serrate, scabrous, obscurely 

 triply-nerved, subsessile, attenuate at each end, ciliate at the base ; 

 scales of the calyx lanceolate, ciliate. 



HAB. Low grounds. Aug. Sept. 7J. ; stem 5 6 feet high, sub- 

 scab. ; pan. loose, few-jl. 



351. RUDBECKIA. 



R. purpurea : scabrous ; lower leaves broad-ovate, narrowed at the 

 base, remotely toothed; cauline ones lanceolate-ovate, nearly en- 

 tire, acuminate at each end ; florets of the ray very long, deflexcd, 

 bifid. 



HAB. Mountains. June July, QJ. ; stem 4 feet high ; Jl. large- 

 rays purp. ; disk brown. 



R. laciniata : lower leaves pinnate ; segments 3-lobed ; upper ones 

 ovate ; pappus crenate ; stem smooth. 



HAB. Swamps. Aug. Ij. ; stem 5 8 ft. high ; lower leaves 3- 

 foliate ; Jl. yell. 



352. BIDENS. Burr-marigold. 



B. cernua : flowers subradiate, cernuous ; exterior calyx as long as 

 the flower ; leaves lanceolate, subconnate, dentate. 



HAB. Ditches, &c. Aug. Oct. ; stem 12 feet high; rays 

 yell., often wanting. 



B. chrysantliemoides : flowers radiate, cernuous ; rays thrice as long 

 as the nearly equal calyx ; leaves oblong, attenuate at each end, den- 

 tate, connate at the base. 



HAB. Wet places. Aug. Oct. <v) ; stem 1 3 feet high ; Jlowers 

 large ; rays 8, lanceol. 



B. frondosa : flowers discoid ; exterior calyx six times as long as the 

 flower ; its leaflets ciliate at the base ; lower leaves pinnate ; upper 

 ones ternate, lanceolate, serrate. 



HAB. Shady wet places. Aug. ; stem 2 feet high, branch. . 

 rays 0, seeds 2-awned. 



GYNANDRIA. 

 MONANDRIA. 



Genera. 



Anther adnate, subterminal, and persistent. Pollinia affix- 

 ed by the base, composed of angular grains, elastically co- 

 fitting. 



