206 BOTANICAL INFORMATION. 



Carices and a dense carpet of Coptis occidentalis, Nutt. cover 

 most part of the black spongy soil, which is but seldom 

 visited by frost and never by a ray of sunshine. 



Abies balsamea and Canadensis both attain considerable 

 size ; the former is found generally near rivers ,• the latter is 

 rare in these latitudes, and I have seen only a few indifferent 

 groves of the same. A few scattered trees of Abies Douglasn 

 grow scattered in Upper Oregon ; not in the green mountains, 

 but here and there on the banks of Columbia river. A spe- 

 cies of Larix occurs on most of the grassy slopes, intermingled 

 with Abies rubra and alba. To these are associated the Sali- 

 cince, as Populus candicans and betulcefolia, Acer glabrum, 

 Crataegus lucida, and Alnus (215) ; the former Acer, and the 

 last, being shrubs. 



Lower parts of these mountains, especially towards Colum- 

 bia river, are often closely beset Tilth Abies rubra, and such 

 tracts are impassable, until the fires have once swept through 

 them which destroy annually an immense quantity of tim- 

 ber.* 



Two low shrubs especially characterize this vegetation, 

 namely, the Mahonia aquifolia, on sunny rocks and slopes ot 

 mountains ; and the Arctostaphylos Uoa ursi, which may be 

 found in abundance almost every where. Linnaa borealts is 

 also very common, with Chimaphila corymbosa, and Pyrola 

 secunda. 



Before we enter on the descriptions of the subregions, we 

 must mention the fact, that Oregon has as many different 

 floras as summer months. No spot is too arid to lodge a pretty 

 plant, no rock too burning ! It is not uncommon in a period 

 of three weeks to see a plain covered with snow, decked with 



* It is a curious fact, that while the forests are left undisturbed, the 

 remains are always composed of such or such kinds in almost unchange 

 proportion. Not so when fire has swept over, and has destroyed the 

 pristine race of trees ; then others spring up, which before were either no 

 at all there, or in the minority. So where Pinus ponderosa is removed by 

 fire, Abies rubra will fill that space to suffocation ; if after a few years »t ,s 

 burnt again, another tree takes the place. 



