1913]  Fernald,— Some Noteworthy Varieties of Bidens 75 
find it growing abundantly on the marshes near the Hillsborough 
River in Prince Edward Island. 
Upon studying the specimens collected, however, the somewhat 
striking fact comes out that, though in all the material from the 
Magdalens and from Gaspé the awns and margins of the achenes are 
retrorsely barbed as in the European Bidens tripartita, the achenes 
of all the material (thirty or more sheets representing three different 
collections) from Prince Edward Island have the margins and awns 
uniformly upwardly barbellate, so that the achenes suggest those 
of the local B. frondosa, var. anomala Porter,! which is known to the 
writer only from marshes of the lower Schuylkill and Delaware rivers 
(in Pennsylvania, New Jersey and Delaware), from the mouth of the 
Androscoggin in Maine, and from the regions of Halifax, Nova Scotia 
and of St. Ann's, Cape Breton. This fact, in conjunction with the 
incident that the three collections of B. tripartita gathered without 
field-study in Prince Edward Island should all show a parallel pe- 
culiarity, indicates that this class of varieties is worthy more atten- 
tion than some students have been inclined to give them. 
On account of its upwardly barbed awns, the plant of the Phila- 
delphia region, Bidens frondosa, var. anomala, was supposed by Asa 
Gray? to be a hybrid of B. frondosa and B. (or Coreopsis) bidentoides, 
a species known only from the region of Philadelphia. But as al- 
ready pointed out by Wiegand “it does not show the necessary inter- 
mediate condition of other characters, and can scarcely be considered 
as such [a hybrid]. "* And in a recent letter to the writer Mr. Bayard 
Long remarks: “ All the localities, you see, are along the lower Schuyl- 
kill and Delaware waters. ... There can be no doubt that anomala 
represents, at least in our area, a tide-water form. All the localities 
definitely point to this. ... Typical frondosa seems very often to 
grow with anomala. ... But despite this, I imagine you are quite 
right in believing anomala to be a real geographic variety. It cer- 
tainly does not have anything to do with B. bidentoides, even in the 
Delaware system. Furthermore, the occurrence of var. anomala in 
the marshes of northeastern Cape Breton or of the Halifax region, 
900 and 750 miles respectively from the locality of B. bidentoides, as 
well as on the lower Androscoggin, all regions which show in their 
1 Porter ex Fernald, Ruopona, v. 91 (1903). 
? Gray, Syn. Fl. i. pt. 2, 296 (1878). 
3 Wiegand, Bull. Torr. Bot. Cl. xxvi. 407 (1899). 
