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PIPEK FLORA OF THE STATE OF WASHINGTON. 67 



THE COLUMBIA GORGE. 

 f 



The wonderful gorge of the Cohimbia River (PI. XVIII), extend- 

 ing a distance of about 50 kilometers (38 miles), presents peculiarities 

 scarcely paralleled elsewhere in the Pacific northwest. The cliffs, ris- 

 ing hundreds of meters verticali}^ present almost every rupestrine con- 

 dition. Some of them are in almost perpetual shadow, others sub- 

 jected to bright sunshine. Some become dry almost with the cessa- 

 tion of the spring rains, others are bathed constantly in the spray of 

 waterfalls. There are thus furnished suitable conditions, both to 

 species from the arid interior and to others that normally flourish 

 only in cool mountain valleys. The resultant association of Cana-' 

 dian or even Hudsonian species with those of the Transition zones is 

 strikingly peculiar. «| 



That such an unusual environment should be the habitat of a con- 

 siderable number of species not found elsewhere might have been 

 predicted. No less than 16 species are practically confined to this 

 region. They are: 



Agrostis hotceUii. Lomatium sp. nov. 



Calamagrostis howellii. Mirnulus alslnoides. 



Delphinium troUiifolium. Pentstemon barrettae. 



Dodecntheon deiitatum. . Poa multnomae. 



Erigeron hoivellii. Sullivantia oregana. 



Erigeron oreganus. Teliima odorata. 



Hcmieva violacca. ValeriancUa aphanoptera. 



Hieracium longiherhc. Viburnum ellipticum. 



Some few others are worthy of special mention. Bolandra oregana^ 

 otherwise confined to the Columbia gorge, reappears on the bluffs of 

 Snake River in Wallowa County, Oreg. 



Synthyris reniformis^ abundant on the Oregon side of the gorge 

 almost at the river's edge, has its real home in the Canadian and Hud- 

 sonian zones of the Blue and Bitterroot mountains. Like several, 

 other species, it does not occur on the Washington side of the Colum- 

 bia gorge. 



A number of the Canadian and Hudsonian species that descend 

 into the Columbia gorge are more or less modified from their original 

 forms and may be regarded as subspecies, when compared with the 

 alpine forms. Such are : 



Ronianzo/fia sitchensis. Saxifraga occidentalis. 



Saxifraga hroncliialis. Valeriana sitchensis. 



Saxifraga caespitosa. 



But a larger number preserve their identity beyond question. Such 

 are: 



Carex macrochaeta. Pentstemon diffusus. 



Chelone nemorosa. Pentstemon rupicola. 



Cornus canadensis. Polypodium hesperiiim. 



Douglasia laevigata. Tofleldia intermedia. 



