Rydberg: Phytogeographical notes 473 



*Betula glandnlosa Phyllodoce glanduUflora 



*Alnus sinuata Kalmia microphylla 



Phyllodoce empetriformis * Ledum glandulosum 



In the Canadian Rockies are added to these: 



Salix alexensis Salix Barattiana 



Salix arbuscidoides Salix Dnimmondiana 



7. Snow drift formation 



This special formation is made up of hydrophytic plants, 

 nearly all of the family Ranunculaceae. The other plants are 

 such as are only occasionally found in these peculiar situations. 

 This formation could be included in the alpine seeps on account 

 of their moisture, but the ground is neither rocky nor does it con- 

 tain much humus. As a rule the soil is considerably clayey. In 

 reality it is a part of the alpine meadow, modified by the slowly 

 melting snowdrifts. The formation is found only in hollows or on 

 gentle slopes, where large snowdrifts have lodged during the winter 

 and the ground does not become bare before late in the summer. 

 The grasses and most other meadow or bog plants could not with- 

 stand such severe conditions. Where the snowdrifts have been the 

 ground is perfectly bare or nearly so, except for these peculiar 

 plants, which appear as soon as the snow has melted and the 

 ground has had time to thaw a few inches deep. Sometimes they 

 even come up through the snow. Hence, the stories of the snow 

 plants often heard of are not altogether " fakes." 



This formation is principally made up of the following plants: 



Southern Northern 



Ranunculus adoneus Ranunculus eximins 



Ranunculus alismaefolius Ranunculus alismaefolius 



Ranunculus stenolobus Caltha leptosepala 



Caltha rotundifolia Caltha Cheledonii 



8. Alpine lakes 



The aquatic flora of the alpine region is rather meagre. All 

 the phanerogams and fernworts found there are found also in the 

 subarctic region, in fact, are boreal plants of wide distribution. 



The flora of the alpine lakes is limited to the following phanero- 

 gams and fernworts: 



