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Muhlenbergna, Volume 8 



moisture, comes out of the ravines upon north or east slopes. 

 It is rarely found on south slopes, even near its upper limit. 

 It is less common in Nevada on the north side of the Truckee 

 river than in the region south of that stream, the slope exposure 

 not being so well suited to its growth. 



The southern limit of the species in Nevada is probably in 

 Douglas county southeast of Lake Tahoe, but it may occur in 

 the mountains west and southwest of Walker lake in Mineral 

 county. I have never explored that region, but as seen from 

 the railroad, it presents a considerable forest growth. In Cali- 

 fornia it is common on the east side of the Sierra Nevada be- 

 tween Truckee and Summit alone the railroad. At elevations 



Fiijure 26. Fruiting branch of Abies Louiana 



between 6500 and 7000 feet it is practically the onh' tree on the 

 north slope which the railroad traverses, although the opposite 

 or south slope across Donner lake is clothed with young Jeffrey 

 pine. .A,bont Summit station, at 7000 feet, it is less common, 

 red fir largei\- taking its place. 



