46 JOHN MACOUN ON THE DISTRIBUTION OF 
boreal ones such as these scarcely a mile apart and both on the same level, we must look 
to more than one cause for their occurrence. The only difference detected by me is one of 
situation and, should those species having a southern origin obtain dry soil, they will be 
found far to the north, while the Arctic species will obtain the necessary coolness in the 
peat bogs and marshes of the undrained areas lying far to the south. 
The practical aspect of this question is one of great importance and, should further 
investigation confirm my views, we can predicate another 100,000,000 acres, in our North- 
West, of land north of the present available area, which has a climate, in the drier parts, 
suitable to the ripening of grain. Should the meteorological station be established at 
Fort Rae, north of Great Slave Lake, I am convinced that its records will show a summer 
temperature quite high enough for the ripening of wheat and barley in that distant region. 
The occurrence of maritime plants in the interior of the continent has called forth 
numerous theories regarding their origin. In my opinion the problem has only one solu- 
tion, viz., the migrations of birds. 
Besides numerous examples of the Chenopodiaceæ and other orders, we have what I 
take to be truly maritime species. These are : 
Ruppia maritima, 
Potamogeton marinus, 
Plantago maritima, 
Scirpus maritimus, 
Heliotropium curassavicum, 
which are found in abundance in certain localities in the interior. These species either 
grow in sea water or so close to it that their roots are constantly in it. 
In the interior they grow either in or on the shores of salt or other lakes which are 
the resort of birds that winter on the sea coast where they occur. 
At Edmonton, 890 miles west of Winnipeg, the farmers cultivate a variety of rye or 
barley under the name of Wild Goose Barley, the first sample of which was obtained from 
the crop of a wild goose in that vicinity. I have seen this grain and am quite sure it 
came from some locality far to the north-west, as it is altogether unlike any sample pro- 
duced in the east. Geese, it may be remarked, are the gleaners in the barley fields at all 
points in the far North-West. 
The salt lakes in which I obtained Ruppia maritima and Potamogeton marinus are 
on the migrating lines of the water birds coming from the sea coast and are the breeding 
places of the ring-billed gull and Bonaparte’s gull, both taking their specific names from 
points on the coast of the southern United States. 
The heliotrope lines the shores of brackish lakes in the great plains as far north as 
lat. 52° while on the sea coast it is only found from Virginia to Florida. 
This is another instance where a plant will bear a severe climate in one locality and 
shuns coolness in the other. Why does it occur so far north in the interior and keep so 
far south on the sea coast ? 
More curious still, last summer I obtained specimens of the western grebe (Podiceps 
occidentalis) on Lake Winnipegosis, where it was breeding in great numbers, and around 
salt springs at the head of the lake the Pacific form of Plantago maritima Was growing in 
profusion. 
