772 REPORT OF NEW JERSEY STATE MUSEUM. 



BIDENS L. 



Key to the Species. 



a. Leaves lanceolate, serrate, undivided. 



b. Rays large and conspicuous, twice as long as the disc or longer. 



B. Icevis, p. 772 

 hb. Rays not more than twice as long as the disc ; very short or wanting. 

 c. Heads nodding after flowering. B. cernua, p. 772 



cc. Heads always erect. 



d. Pappus awns downwardly barbed. B. connata, p. 773 



dd. Pappus awns upwardly barbed. B. Udentoides, p. 773 



aa. Leaves, some or all of them, pinnately 1-3 parted. 

 6. Rays rudimentary or wanting. 

 c. Achenes flat. 



d. Outer involucral bracts 4-8 mm. ; achenes nearly black. 



B. frondosa, p. 773 

 dd. Outer bracts 10-16 mm. ; achenes brown. B. vulgaia, p. 773 

 cc. Achenes linear. B. bipinnata, p. 774 



bb. Rays large and conspicuous. 



c. Segments of the leaves lanceolate. ' B. trichosperma, p. 774 



cc. Segments of the leaves linear lanceolate. 



B. trichosperma tenuiloba, p. 774 



Bidens Isevis (L.). Large Bur-Marigold. 



Helianthus lavis Linnaeus, Sp. PI. 906. 1753 [Virginia]. 



Bidens lavis Britton 147. 



Bidens chrysanthemoides Knieskern 19. 



Swamps, especially bordering rivers and large streams. Mid- 

 dle and Cape May districts, frequent, also in the northern coun- 

 ties and occasional on the coast. 



A particularly characteristic plant of the Delaware rivftr 

 shores and tidal marshes, its large flowers closely resembling 

 those of Helianthus or Rudbeckia. 



Pi. and Fr. — Mid- August into October. 



Middle District. — Delair, Pish House, Washington Park, W. Deptford, 

 Center Square, Cooper's Creek, Swedesboro. 

 Coast 5*Wf.— Tuckahoe (S), Five-Mile Beach. 

 Cape May. — Cape May. 



Bidens cernua L. Nodding Bur^lVlarigold. 



Bidens cernua Linnaeus, Sp. PI. 832. 1753 [Europe]. — Britton 147. 



Wet, open swamps ; frequent in the northern counties and ap-' 

 parently rare southward in the Middle district. 



PI. and Pr. — Mid- August into October. 



Middle District— 'Nt-w Egypt, Pemberton (C), Swimming River (C), Med- 

 ford (S). 



