

1814.] and on Vegetation. 2J 



a proof that besides the latitude and the height above the level of 

 the sea, there is still another circumstance, namely, the neighbour- 

 hood of- the mountains, to be taken into account. 



The melting of the snow shows clearly the great difference be- 

 tween the temperature of Upsala and the lake Yngen ; for the 

 seasons do not vary more from each other in different climates than 

 they do in these two places*] n the early part of the year, and espe- 

 cially in the time that the ice breaks up. This happens at Upsala 

 between the 14th and 23d of April ; but at the lake Yngen, never 

 sooner than between the 12th and 20th of May.* 



The variations in the vegetation correspond with the differences 

 observed in the temperature of these two places. Various plants 

 reach their northern limit before they arrive at the lake Yngen, 

 which, notwithstanding, continue to vegetate around Upsala. There 

 are likewise various northern plants which reach their southern 

 limit at Upsala that stiil continue to flourish by the side of the lake 

 Yngen. These plants cover broader or narrower zones of the earth's 

 surface, which may be pointed out by lines, both on their north 

 and south side. On the one side, the too high temperature prevents 

 the plants from growing ; on the other, the too low temperature. 

 Now these limits, as well of northern plants towards the south, as 

 of southern plants towards the north, mark with precision the tem- 

 perature of the earth at the respective places. 



Upsala. 



The following are the southern plants which reach their northern 

 limit not far from Upsala, and which are quite unknown in the 

 country surrounding the lake Yngen. 



The oak in the neighbourhood of Upsala requires the shelter of 

 the acclivities of mountains, and scarcely passes the river Dal, where 

 the temperature is 43*34°. In Vermeland it is found only in the 

 neighbourhood of the lake Venner, and about Kummelo. The elm 

 (ulmus campestris) can bear a somewhat more severe climate ; but 

 it will not grow at the lake Yngen. The case is the same with the 

 following plants : Cratcegus oxyacanlha, primus spinosa, rosa 

 canina, rhamnits catliurticus, salix j'ragilis, mespilus coloneaslei; 

 rubus ceesius, ononis arvensis (uncommon also about Upsala), pri- 

 mula veris, puhnonaria officinalis, stratiotes liydrocharis, lypha 

 anguslifolia, anemone Pulsatilla, cenlaurea scaliosa, sphevu filupen- 

 ilnla, butomuSf lychnis viscaria, rumex crispus, con wallaria polygon 

 nal/tin, ornithogallum luteum, asclepias vine e toxic tun, mutva rotun- 

 difolia |3 thulktrnm Jluvum, agrimonia, convolvulus arvensis, lordy- 

 lium uiithriscus, hettonia, anchusa ofjicinilis, cynosuuc cceruUus, 

 phalaru phleoides, tcirpus sylvaticus and caricinus, carex uuuicata 

 andjlacta, pMjllophoru. 



• At Abn it bappefll mi A|iril 16 or 17 ; at Umro, on May 7; lit Uloo, on 

 May *; at Smlankyla, lat. 67° gtf, oa May IS; at Ulsjocki, Taua-cif, ou Ma/ 

 *).— ituUuth. 



