Vol. 26 



No. 8 



BULLETIN 



OF THE 



TORREY BOTANICAL CLUB 



AUGUST 1899 



Some Species of Bidens found in the United States and Canada 



By K. M. Wiegand 



Several years ago, while collecting in the vicinity of Ithaca, 

 N. Y., the writer found a number of specimens of Bidens connafa^ 

 on which the awns were upwardly barbed. Until recently * such 

 specimens have been considered to be hybrids with some species 

 of Coreopsis^ but in the plants in question there w^ere no characters 

 to warrant such an assumption further than the mere fact of the 

 difference in direction of the barbs. It was thought best, there- 

 fore, to attempt a study of this group to determine, if possible, 

 the exact affinities of the various forms and the constancy of some 

 of the more important characters. B. cernua and B. laevis^ in 

 Central New York, have also been much confused, mainly, how- 

 ever, because of the presence of the form here distinguished as B. 

 cernna intcrnicdia. It was decided on this account to include 

 these two species also In the proposed study. 



Since that time a large mass of material has been collected and 

 many field notes have been made from plants growing in various 

 portions of New York State. To supplement this, specimens have 



■ 



been examined from many other localities throughout the United 

 States and portions of Europe and Asia. In September, 1897, the 

 writer was able to separate the B. connata coinosa Gray as a dis- 

 tinct species, and now the study has reached such a stage as to 

 warrant the publication of all the results. 



^Britton, Bull. Torr. Bot. Club, 20: 280. 1893. 



[Issued 17 August.] 



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