[Vol. 2 



86 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



1 



ice in the southeast of Norway ; but the direct land connection 

 facilitated the spread of all species of plants. 



Betula odorata was an early immigrant, and with it were 

 a number of other plants of which fossil remains have been 

 found, especially in peat-bogs in the southeast of Norway, 

 namely, Betula nana, Carex ampullacea, C. filiformis, Cicuta 

 virosa, Comarum palustre, Empetrum nigrum, Equisetum 

 fluviatile, Ilippuris vulgaris, Juniperus communis, Meny- 

 anthes trifoliata, Myriophyllum spicatum, Nymphaea alba, 

 Potamogeton natans, Scirpus lacustris, Vaccinium Vitis- 

 Idaea, Z annichellia polycarpa. 



But in addition to these, it may probably be assumed that 

 the following species, which are found as subfossil remains 

 from the subarctic or partially arctic period in Swedish peat- 

 bogs, 2 may have migrated into Norway by this southeastern 

 road as soon as some of the nearest land areas were free from 

 ice. These are Andromeda polifolia, Arctostaphylos alpina, 

 A. Uva JJrsi, Batrachium confervoides, Diapensia lapponica, 

 Montia fontana, Myrtillus uliginosus, Oxyria digyna, Phrag- 

 mites communis, Polygonum viviparum, Populus tremula, 

 Potamogeton filiformis, P. praelongus, Salix aurita, 8. caprea, 

 S. cinerea, S. phyllicif olia , S. repens, Scheuchzeria palustris, 

 and Stachys sylvatica. During this period Hippophae rham- 

 noides also immigrated to Sweden, but as it spread along the 

 east coast of that country and thence through Jemtland to 

 the north of Norway, this could not have taken place until 

 much later, after the last of the central inland ice had melted. 



THE PINUS SYLVESTRIS PERIOD 



After Betula odorata, but during the so-called Ancylus 

 Period in Sweden, Pinus sylvestris migrated to the south- 

 east of Norway, while the cliimite was still comparatively 

 cold; but, as we may gather from some of the plants that 

 occur, especially in the latter part of the pine zone, the tem- 

 perature became rather rapidly warmer. 



J. Holmboe has found in the peat-bogs of Norway the fol- 



ing fossil plants in the 



1 By J. Holmboe ( '0.3 ) . 



8 By Gunnar Anderason ('96). 



Alisma Plantaao, Alnus 



