146 Rhodora [AUGUST 
THE SPECIFIC IDENTITY OF BIDENS HYPERBOREA AND 
B. COLPOPHILA. 
M. L. FERNALD. 
In 1885 Mr. J. M. Macoun collected at Rupert House, James Bay, 
a little Bidens which was subsequently described as B. hyperborea 
Greene.'! This collection consisted of three small plants each with 
one head and with the foliage badly mangled. Somewhat later the 
present writer,” in attempting to identify a characteristic plant of 
the tidal reaches of the rivers of the Gaspé Peninsula, finally decided 
that the Gaspé plant was best placed with B. hyperborea, the achenes 
of the two being exactly alike in their technical characters, that is, 
they were flat linear-cuneiform strongly striate achenes, without the 
suberous margins and prominent ribs which are so characteristic of 
B. cernua. Still later, in 1909, material collected in southern Maine, 
along Winnegance Creek, was referred by Fernald & Wiegand * on 
account of its achene-characters to B. hyperborea. Subsequently, in 
studying this material and some other specimens from adjacent waters 
of the lower Kennebec and Androscoggin systems in Maine, characters 
were found which seemed to set this Maine plant off very definitely 
from the little Gaspé plant which had formerly been identified with 
B. hyperborea, and the Maine plant was consequently described as 
B. colpophila Fernald & St. Johnt During the summer of 1916 
Mr. Bayard Long and the writer collected plants of this affinity exten- 
sively in Maine, where they abound on the tidal reaches of the 
Penobscot and Kennebec systems, and other material heretofore un- 
identified shows the plant of the lower Penobscot and Kennebec to 
occur also on the brackish marshes of the Merrimac in Essex County, 
Massachusetts. 
The writer’s attention has been redirected to this group of plants 
by Dr. Earl E. Sherff, who has very kindly called attention to the 
fact that the Gaspé plant, which had been originally identified with 
B. hyperborea, is very unlike the original James Bay material in some 
1 Greene, Pittonia, iv. 257 (1901). 
2 Fernald, Ruopora, x. 201-203 (1908). 
3 Fernald & Wiegand, Ruopora, xii. 120, 144 (1910). 
4 Fernald & St. John, Ruopora, xvii. 21 (1915). 
