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The silver fir or weisstanne (P. picea ) is more sparingly dis-tributed than the last named. It is common in the Jura , andin parts of the Engadine and Southern Tyrol , but I do not re-member to have very often noticed it in the Swiss or other dis-tricts of the Western Alps. In general appearance it resemblesthe spruce fir, but the silvery tint of its bark and of the underside of its leaf renders it easy to be distinguished. In the Jura it reaches a height of 5000 feet on the Dole, but in the En gadine it has rather a lower range. It has, however, beenobserved in the Pennine chain up to about 6200 feet.
Sporadic also in its distribution, but occasionally veryabundant, is the Scotch fir (P. silvestris), which grows up toabout 6000 feet. It is rare in the French , Piedmontese, andSwiss Alps , where it seems to be generally confined to thealluvial land. It is, however, occasionally found in the moun-tains, but does not generally form extensive forests. In theSouthern Tyrol it is more abundant, and extends to a con-siderable height above the sea, perhaps not less than 5000 feet.
Last comes the arolla or arve (P. cembra ), one of the mostbeautiful of all, with its glossy dark-green brushes and denseclustered foliage. Though in many districts very abundant,it is decidedly a local tree. Tschudi mentions, as among themost celebrated habitats, the Frela above Li vino, the north sideof the Munster Thai, the neighbourhood of the Bernina, andthe Stelvio. I can answer for the abundance of it in the lasttwo localities; for it is one of the great charms of the mountainsabout Pontresina and Trafoi (on the eastern side of the Stelvio pass ), where it grows as far up as 8000 feet above the sea.I have also seen it near Zermatt , especially in the Zmutt-thal,in Dauphind, on the south side of the Dent Parassee in theMaurienne , about the Ainpezzo Pass, and indeed generallythroughout the Dolomite districts. Tschudi states that it occurssparingly in the mountains about the w r est of the Diablerets,(where I have also- seen it), in the Gentel-thal and Engstelen-