418 Wiegaxd: Some Species of Bidens 



closely serrate : heads as In the type but more numerous : ra}\s 

 variable but commonly longer than in the type (11/-2 times 

 length of disk). 



Massachusetts to Kentucky, and westward to Kansas and the 

 Pacific coast. 



Specimens examined from : — Massachusetts : Tnckcrnuviy 

 luixon, Cliambcvs^ Szvaii^ Collins^ Yoiin^, Froliock, Connecticut : 

 Eaton. Ne*v York : Stcivart^ Wicgand. New Jersey : llaxauicr 

 and Maic)\ Pennsylvania : Bri^itou, Kentucky : Short, KcaDicy : 

 no. 475. Ilh'nois: Bcbb^ Kansas, Riley Co., Car/cton, Wyoming : 

 Nelson^ no. 2724. British Columbia : Macoiin, no. 457. Wash- 

 ington : Siiksdorfj no. 932, 933. Oregon: Cusick. 



Bidens cernua Integra var. nov. 



Large and stout, resembling var. clliptlca^ but the large leaves 

 are not so much narrowed at the broad connate base, and are 

 minutely serrate or nearly entire. 



Missouri and Nebraska. 



Specimens examined: — Missouri : Jackson Co., Bush, no. 165 

 and no. 34. Nebraska: Hooker Co., R^uibcrg, no. 1697; at 

 Ainsworth, Clcmaits, no. 2920. 



BidcHS cernua is one of the most widely distributed species of 

 the genus, and is found throughout luirope and Asia as well as 

 across the entire northern portion of North America. It grows 

 preferably in very damp situations or in water, and in most 

 parts of the eastern United States may be found abundant in 

 ditches, along the borders of wet swamps, and especially on the 

 muddy banks of lakes and rivers. ' 



It is exceedingly variable in stature, foliage and length of in- 



I 



volucre and rays. Nnumerous specimens also connect the 

 type with B. Iac7ns by an almost complete chain of intermediate 

 forms. The essential characters of these two species are almost 

 exactly the same, and one must depend for specific distinction on 

 those characters to which is due the difference in general appear- 

 ance. However, certain lines can be drawn which are fairly dis- 

 tinct, and in the interest of clearness it seems much better to break 

 up the group as has here been done. 



The specimens representing the typical form resemble very 



