CHRISTENSEN: ARCTIC PTERIDOPHYTA 67 
places the vegetation may be remarkably rich, both in 
species and individuals, and even trees (birches) attain 
here a really considerable size. Ferns are here repre- 
sented by several species which do not occur elsewhere 
in the arctic regions; for instance, Dryopteris filix mas, 
. Linneana, D. phegopteris, D. dilatata, Polystichum 
ackeke Athyrium alpestre, Asplenium viride, and species 
of Botrychia. In this region the fern vegetation reaches 
its farthest north, in Grinnell Land, 81° 50’ N. lat., where 
Cystopteris fragilis, Equisetum arvense, E. variegatum, and 
Lycopodium selago were found. In the Hayes Sound 
region, at about 79° N. lat., the ferns are rather numer- | 
ous, and the botanist of the Sverdrup expedition, 1898- 
1902, Dr. Simmons, named a valley in the outer part of © 
Hayes Land (Buchanan Strait) Lastrwa Valley, where he 
found Dryopteris (Lastrea) jragrans in plenty. 
The coast of East Greenland is colder than the west 
coast, because the huge masses of sea ice find their way : 
out from the Arctic Basin to the Atlantic Ocean between _ 
Iceland and Greenland. The coast opposite Iceland is 
ice-covered to the very shore and here vegetation ae 
practically wanting, but south and north of here an ice- _ 
_ free foreland is to be found, which, especially northwards, : 
_ (from about 70° to 76° N. lat.) is of considerable breadth. = 
‘Five species ries ets aati emia’ —_ Equi- a 
