106 DISTRIBUTION OF BRITISH PLANTS 



of the Swiss mountains has also about the same limits as 

 the P. Picea. The upper line of P. Picea is estimated to 

 be at 4550 feet. Dryas octopetala, Saxifraga oppositifolia, 

 Erigeron alpinus, &c. occur in this region. (The mean 

 temperature of the earth, where P. Picea fails, appears to 

 be 41° or 42°.) 



4. ( Upl.) The Higher Ascending Region (regio mon- 

 tana superior) is marked by woods of Fagus sylvatica. 

 Corylus Avellana, Quercus Robur, Ulmus, Tilia, and cul- 

 tivated Cherry are seen almost half way up the region, 

 and Pears a little lower. (The line of Beeches exceeds 

 4000 feet. The mean temperature of the earth where this 

 tree ceases is 43°, that of the air 38^°.) 



5. (Asc.) The Lower Ascending Region (regio montana 

 inferior) is characterised by the Walnut tree, the average 

 elevation of which is estimated at 1950 feet, Swedish mea- 

 sure ; but in certain situations it ascends several hundred 

 feet higher. (It appears to fail where the temperature of 

 the earth is about 47°.) 



6. (Bas>) The Plains, or Base of N. Switzerland, where 

 the Vine is cultivated. 



In the Flora Carpatorum, Wahlenberg distinguishes the 

 regions, as below : — 



1. (Pla.) The Plains, or Region of Corn and Fruit, 

 rising equally high as in Switzerland. Genista tinctoria 

 occurs here. The Vine and Walnut are remote from the 

 limits of the Flora Carpatorum, the former ascending 960, 

 and the latter 1300 feet above the level of the sea. 



2. ( Upl.) The Upland, or Region of the Beech, is here 

 richer in plants than in the N. of Switzerland. Symphy- 

 tum tuberosum, Asarum europaeum, and Avena planiculmis 

 are found in the present region. The limit of the Beech 



