A Study of the Vegetation of 



Adsere. Alnus-Sali.v associes 90 



Subsere. Natural reforestation in cut-over areas and in burns 91 



Hydrosere 100 



Chara-Potamogeton associes 101 



Nymphaea-Potamogeton associes 102 



Scirpus-Typha associes 103 



Eleocharis-Carex associes 104 



Wet meadow associes 105 



Flood-plain forest associes 107 



Ruderal vegetation 109 



Conclusion 1 1 1 



INTRODUCTION 



No one at all botanically inclined can travel through south- 

 eastern Washington without being impressed with the marked 

 changes which a distance of only a few miles may show in the 

 vegetation. Traveling eastward from a point fifty miles west of 

 the Idaho state line, one passes from a region of scab-land sage- 

 brush through one of rolling hills covered with bunch-grasses. 

 Upon steadily ascending the great Columbia Plateau, the bunch- 

 grasses give way to well developed prairies, and these in turn, 

 near the Idaho line, to forests of yellow pine, Douglas fir, white 

 fir, tamarack, and cedar. Or starting from Spokane in the central 

 part of eastern Washington and traveling southward, one soon 

 leaves the pine woodland of the Spokane gravels and passes again 

 through the rolling prairies. Projecting above the surrounding 

 sea of prairie-covered basalt are islands of quartzite, the tops of 

 lofty mountains almost buried under the basalt. These may be 

 covered with grass land on the windward side, while at a distance 

 of a few meters over the crest the prairie may give way to rather 

 dense forests. Cut through the layers of basalt, in a mighty 

 canyon, 1,600 feet deep, the Snake River winds its way through 

 the prairie belt. Upon descending into the canyon one finds the 

 bunch-grasses and sagebrush vegetation growing in a climate 

 markedly different from that of the plateau above. Far south- 

 ward from the canyon of the Snake River rise the pine-covered 

 foothills of the Blue Mountains. 



Such is a brief glance at the wonderful field for investigation 



2 



