[Vol. 2 



70 ANNALS OK THE 



Picea excelsa, which immigrated much later than Pinus 

 sylvestris, supplants the latter in favorable localities in the 

 east of Norway; hut in the west its field of distribution is 

 very small, and extends only to latitude 69 °N. Farther 

 north, in the interior of Finmark, small spruce forests do 

 indeed occur, but they are formed of Picea obovata. 



The forests that are formed of Pinus sylvestris are light, 

 but as they often grow upon dry, poor soil, they are poorly 

 furnished with vegetable species. There may occur scattered 

 specimens of Betula odorata, Alnus incana, Juniperus com- 

 munis, Sorbus Aucuparia, and Populus tremula, ami then a 

 poor ground vegetation of mosses (e.g., Polytrichum juni- 

 perinum), and lichens (e.g., Cladoiiia rangiferina, Cetraria 

 islandica, and Peltigera), among which grow some easily 

 contented higher plants, especially Aira flexuosa, Arctosta- 

 phylos officinalis, Calluna vulgaris, Kmpetrum nigrum, Fes- 

 tuca ovina, Luzula pilosa, Melampyrum sylvaticum, Pteris 

 aquilina, Trientalis europaea, Vaccinium Myrtillus, V. ulig- 

 inosum, and V. Vitis-Idaea. 



Where this forest, from some cause or other, has been de- 

 stroyed, extensive heath-lands are often formed, consisting 

 chiefly of Calluna vulgaris, among which occur Empetrum 

 nigrum and species of Vaccinium, as also Antennaria dioica, 

 Aira flexuosa, Campanula r otundif olia , Festuca ovina, Nardus 

 stricta, and others. 



Picea excelsa forms forests on more fertile soil; but as they 

 are very dense and dark, other trees have difficulty in forcing 

 an entrance, and even the ground vegetation is as a rule very 

 poor, owing to the want of light. A thick carpet of mosses 

 (especially Hylocovtium splendens) covers the ground, and the 

 only plants that thrive are fungi, Polystichum spinulosum and 



some other ferns, JAnnaea borealis, Milium effusum, Oxalis 



Acetosella, Pyrola uniflora, and others. 



Where the forests of Picea are less dense, or whore Pinus 

 sylvestris grows upon a more fertile soil, these conifers may 

 be mingled with various deciduous trees, and in the lower 

 districts even with less hardy deciduous trees, which other- 

 wise belong to the Oak Zone. The ground vegetation in such 



