WiEGAXi) : Some Si'Ecies of Bidens 419 



closely those of Europej although more commonly radiate. 

 They are all plants of low or medium stature, having large, more or 

 less clustered heads with rays scarcely longer than the disk, some- 

 times entirely wanting ; and what is more important, long, linear- 

 lanceolate leaves, broad at the base and acuminate, with distant 

 teeth. The heads are somewhat paler in color and the lower are 

 on short branches close to the stem. 



The plants may flower when very small and dwarf. Such 

 specimens usually hav^e a large involucre and shorter more entire 

 leaves. In addition, there is a bog form analogous to the one 

 described under B, coiniata. These plants grow on floating logs 

 and in Sphagnum, and are very dwarf (4-14 cm.), with very small 

 (2-4 cm.) spatulate entire leaves. On the other end of the log, 

 however, may be larger specimens easily recognized as normal. 

 This form is possibly the /?. niiJiinia of Hudson, but in this coun- 

 try at least it is evidently not to be distinguished from the type.. 



A comparatively distinct form has been separated as var. 

 cUiptica, The large size of the plant, the broader leaves tapering 

 at the base and closer serraturcs together with the longer rays has 



L 



led to its being included often with the next species, but a com- 

 parison of the specimens shows that it is much more closely re- 

 lated to />. ccniua. The shorter rays and foliaceous involucre are 

 the best characters by which it may be separated from B. lacvis. 



B, ccrmia, like many other species of the genus which enter 

 the confines of Missouri, has undergone variation. The form 

 here described as var. intcgra is very distinct in appearance, and 

 constant enough to warrant its separation. The flowering period 

 of B, ccrnua is from Aug. 10 to Oct. 15. 



9. Bidens laevis (L.) B.S.P. Prelim. Cat. N. Y. 29. 1888. 

 Hc/ianthns laevis L. Sp. PI. 906. 1753. PL Gronov. 



Bidens chrysanthemoides Michx. Fl. Bor.-Am. 2 ; 136. 1803. 

 Also of Willd. Sp. PI.; DC. Prod.; Elliot, Fl. S. C; Torn FL N. 

 U. S.; T. & G. Fl. N. A. var. o. and ;-. 



Bidens quadriaristata DC. Prod. 5 • 595- 1836. 



Coreopsis Bide?is W'dXt. PT Car. 215. 1788. 



? Coreopsis perfoliata \\'alt. Fl. Car. 



Stem (.5—1 m. tall) glabrous, tinged with purple, erect, branches 



