126 BOTANICAL GAZETTE. 



movement of large masses of snow, I have seen trees six feet higli 

 torn up by the drifts. Large drifts are generally formed near the sum- 

 mits of steep banks about timber line and easily prevent trees obtain- 

 ing a foot hold upon the steeper slopes. If such a slope at its summit 

 has a comparatively level area protected by a higher summit some 

 distance beyond, there will be a sort of double timber line, one at the 

 foot of the bank and one some distance beyond its summit, but the 

 upper one is formed by trees, almost prostrate, bent and twisted 

 downward and distorted into all manner of shapes by the weight of 

 the snow. They owe their existence to the nearly level habitat which 

 prevents them from being torn up by a downward motion of the 

 snow. Without a higher protecting ridge this second timber line 

 would be impossible on account ot the winds which would keep the 

 summit clear of trees. 



The prevailing winds are from the west from which direction the 

 snow is drifting almost continuously throughout the winter. On al 

 most any clear winter day the banners and streamers of snow can be 

 seen coming from the summits. In consequence of the prevalence of 

 western winds, the largest dritts are on the eastein slope and on the 

 eastern slopes of north and soiKh spurs and timber line is higher on 

 western slopes. This is plainly seen upon the smaller spur^ having 

 a north and south direction. If the soil and slope are the same upon 

 both sides, the tree line will round the spur from the western expos- 

 ure and fall on reaching the eastern si pe five or more hundred feet. 

 The wind storms are most violent on the high ridges and divides and 

 prevents tlie growth of trees in such places, but their direct destruc- 

 tive influence reaches only two or three hundred feet each side of 

 the summit and a lower limit to the forest is due to the drifting snow. 

 Sometimes but rarely a line of prostrate trees between wind and 

 snow can be found, just over the summit out of re:ich of the wind 

 and not far enough down the slope to enable the drift to obtain a hold 

 and uproot them., Picea Engelmanni does not record in its growth the 

 direction of the wind as Finns aristata sometimes does in exposed sit- 

 uations when the twisted and turned branches plainly show that the 

 prevailing winds are from the west. The limit of trees being deter- 

 mined by the winds and the snows drifting about the summits, then 

 timber line depends very much upon the height of the dividing ridge 

 and the higher the mountain the higher the tree lire, other conditions 

 being the same. 



Timber line reaches its highest altitude where there is a large 

 area of high elevation extending long distances from dividing ridges. 

 — T. S. Brandegee. 



Notes on some Californian Plants. — A residence of a year 

 and a half in the Southern part of California, principally in the neigh- 

 borhood of Los Angeles, has enabled me to study and collect the 

 plants of that region, and I propose giving the readers of the Gazette 

 some account of a few of the most interesting features of the vegeta- 

 tion of that locality. I shall select for my purpose only the more 



