1911] Fernald,— Expedition to Newfoundland 143 
more Southwestern plants which together with the Boreal make up 
941 per cent of the flora of the island; a flora which, it is almost need- 
less to say, must have reached Newfoundland since the receding 
toward the north of the Pleistocene glaciers. 
Besides by human transportation there are five methods by which 
plants are commonly supposed to have reached islands: by trans- 
portation by birds, by ocean-currents, by floating ice and logs, by winds, 
or by having crossed on a formerly existing land-bridge. All of these 
methods may well have been effective in bringing to Newfoundland 
the plants of Group I, the Boreal types, but before accepting them as 
the sources of the floras of Groups II and III, the typical Canadian 
and the Southwestern plants, we may well consider them in some 
detail. 
Birps. There has long been a strong tendency, based in part on 
the notes of Darwin and others, to believe that many difficult problems 
of plant distribution are to be explained by assuming that the seeds 
or fragments of the plants have been transported by birds. But it 
can only be said that the best evidence is opposed to this explanation 
of the origin of the floras of the more remote islands of the North 
Atlantic. In their exhaustive treatises on the sources of the Faeróese 
flora Warming and Ostenfeld, though diametrically opposed in their 
final opinions (the latter urging the necessity of a post-glacial land- 
bridge from Scotland to the Faeróes, the former maintaining that no 
such bridge is demanded), both affirm that the number of plants 
carried by birds over such distances are almost negligible. This con- 
clusion is based upon the studies of two eminent Danish ornithologists 
and is so applicable to the present problem that I quote freely from 
both Ostenfeld and Warming. The former says: 
“As I also [formerly] laid some stress on the migrations of birds (all 
the more, perhaps, because I held the other disseminating agencies 
to be of little value) I applied to an eminent Danish ornithologist, 
Mr. Knud Andersen, who has made a special study of the birds 
of the Faerées,! and he very kindly gave me the information I wanted. 
If we consider how the migrating birds would carry the seeds 
with them, it can only be in one of two different ways, either in the 
alimentary canals or adhering to their beaks, feet or feathers. With 
1 Knud Andersen: Meddelelser om Faerfernes Fugle med saerligt Hensyn til 
Nolsø, I and II. (Vidensk. Medd. f. d. naturh. Forening i Kj@benhavn 1898, p. 315, 
1899, p. 239). 
