174 GEOEGE B. RIGG 



glacier in Cook Inlet. Some very small seedlings of Populus 

 trichocarpa were found growing in the gravel fronting Grewingk 

 glacier, and this species with Alnus sinuata flourished where there 

 was soil mixed with the gravel. Picea sitchensis grows abundantly 

 on the neighboring mountain sides. 



Heller ('12) in speaking of the vegetation of Prince William 

 Sound says: ''The tundra occupies wet swampy ground that the 

 forest cannot invade, the complete saturation being fatal to tree 

 growth. The forest occupies the drier ground. The tundra 

 occurs as islands in the forest area and consists chiefly of a heavy 

 covering of mosses and shrubs which hold much moisture." 



Wind is certainly not a factor in the production of the Yakutat 

 "prairie" (tundra), for it is wooded practically all around with 

 trees that show no distorting effect of wind. 



Sphagnum is very abundant in the Yakutat region outside of 

 the bogs and even outside of the tundra. It is common around 

 small ponds and is the dominant moss in much of the wooded 

 region. It is by no means confined to forming a dense growth on 

 the ground. It runs over fallen tree trunks and up-turned roots 

 of trees. In one case a considerable growth of it was found with 

 other mosses on the upturned roots of a fallen spruce at a height 

 of 6 feet from the ground. 



CORDOVA, MAY 26 



At Cordova a small sphagnum bog was found that was closely 

 bordered by a forest of spruce and hemlock. This is similar to 

 the situation of bogs in the Puget Sound region and is quite 

 different from the situation of the bogs at Dixon Harbor and at 

 Yakutat Bay. This Cordova bog occupies all of the flat area 

 and the bordering forest is on a steep hillside. Empetrum nigrum 

 and Kalmia glauca are the characteristic woody evergreens of 

 this bog. Sphagnum is dominant over its whole area. Beneath 

 the surface is a mass of brown fibrous peat having a maximum 

 depth of 3 feet. This bog is confined to an undrained place and is 

 bordered by the hillsides and by the rocks that prevent the out- 

 flow of water. When a cavity was scooped out in this peat, 

 water quickly accumulated in it just as it does in Puget Sound bogs. 



