324 



MINNESOTA BOTANICAL STUDIES 



plants rare in the Selkirk range, and of very local distribution, while 

 those of the north moraine are nearly all the common plants found 

 everywhere in similar situations throughout the region. The flora 

 of the south moraine ceases abruptly where the moraine comes in 

 contact with the schist talus slopes of the adjacent hillsides. These 

 hillsides bear many of the plants found on the north moraine, and 

 almost none of the plants found exclusively on the much nearer 

 south moraine. They have a much richer vegetation and more 

 abundant flora than either moraine as they have been historically 

 much more stable, and have much older soil with a considerable 

 accumulation of humus. ^ 



In seeking for the causes of the peculiar plant distributions 

 noted above, it is easily seen that they can not possibly be due to 

 historical reasons. Plants have had equally good opportunities of 

 reaching both moraines. Plants can easily migrate across the region 

 of ground moraine at the foot of the glacier. Seeds of the charac- 

 teristic plants of the north moraine, growing, as most of them do, 



iThe abrupt transition of vegetation in passing from moraine to hillside is well shown 

 by the following transect, 1 cm. wide, taken across the oldest part of the south moraine 

 and up the adjacent hillside to a height equal to the top of the hioraine. 



Moraine 

 m.- 



-1 m. 



2 Salix arctica 



4 Moneses uniflora 



1 Salix vestita 



2 Salix vestita 

 1 Salix vestita 



1 Salix arctica 



2 Erigeron uniflorus 

 1 Anemone parviflora 



1 Antennaria pulvinata 

 7 Salix arctica 



2 Salix vestita 



3 Anemone parviflora 



2 Antennaria pulvinata 

 1 Erigeron uniflorus 

 7 dm. stony 



1 Anemone parviflora 



3 Salix arctica 



2 Dryas octopetala 

 2 Anemone parviflora 

 2 Dryas octopetala 

 2 Abies lasiocarpa 



(seedlings) 

 1 Salix arctica 



1 Salix vestita 



5 dm. stony 



2 Antennaria pulvinata 



6 dm. stony 

 1 Arnica sp. 

 1 Polystichum lonchitis 

 1 Salix nivalis 

 1 Picea Engelmanni 



(seedling) 

 1 Saxifraga oppositifolia 

 1 Salix vestita 

 11.9 m.^ — 12.3 m. stony 

 1 Polygonum viviparum 



Base of Moraine 



13 m. — ISm. Bare space beneath 

 large spruce tree 



1 m. — 2 m. 



2 m. — 3 m. 



3 m. — 4 m. 



4 m. — 5 m. 



5 m. — 6 m. 



6 m. — 7 m. 



7 m. — 8 m. 



m. — 9 m. 



19 m. — 20 m. 



20 m. — 21 m. 



21 m. — 22 m. 



On large limestone boulder fallen from 

 moraine. 



15 m. — 16 m. 1 Salix vestita 



16 m. — 17 m. 2 Salix vestita 



17 m. — 18 m. 2 Anemone parviflora 



Lichens and moss 

 Beginning of hillside 



18 m. — 19 m. 5 Pyrola secunda 



2 Rhododendron albiflorum 

 1 Arnica sp. 



1 .-\bies lasiocarpa 25 cm. 



in diameter 

 Fallen log 



2 Rubus pedatus 

 2 Pyrola secunda 

 1 Valeriana sitchensis 

 1 Cassiope mertensiana 

 4 Rubus pedatus 

 1 Rhododendron albiflorum 

 1 Vaccinium membrana- 



ceum 

 1 Cassiope mertensiana 



22 m. — 23 m. 11 Rubus pedatus 



23 m. — 24 m. 5 Rubus pedatus 



1 Mitella Breweri 



2 Vaccinium membrana- 



ceum 

 4 Lutkea pectinata 



6 Lutkea pectinata 

 1 Arnica sp. 

 1 Luzula Piperi 

 1 Mitella Breweri 



7 dm. schist rock, covered 

 with Lutkea pectinata 



1 Mitella Breweri 

 1 Luzula Piperi 

 Lutkea pectinata through- 

 out 

 1 Cassiope mertensiana 



1 Luzula Piperi 



2 Mitella Breweri 



24 m.— 25 m. 



25 m. — 26 m. 



26 m. — 27 m. 



