52 Postelsia 
Along the border of these forest openings is 
generally a zone of low, bushy, in many cases 
stunted looking trees of Thuja plicata and Tsuga 
heterophylla. Now and then one encounters a 
peculiar adaptation of Pinus contorta to such a 
habitat. When this species occurs in these mod- 
ified bogs it is generally found fringing the edge, 
although sometimes it has succeeded in estab- 
lishing itself: well out in the open. In either 
case, the tree does not attain any considerable 
height, (3-8 meters) and grows apparently very 
slowly. In appearance it offers a peculiar con- 
trast to the other trees around as the branches 
are all clustered in a palm like crown at the top 
(Pl. XID): Frequently one observes heremrne 
phenomenon of old cones adhering far down on 
the main stem. These have evidently been pro- 
duced on adventitious shoot. 
¢ -* Porest.of the river valleys: 
Under the conditions which these natural 
drainage courses call forth, the vegetation shows 
itself in a somewhat different aspect from that 
developed at similar altitudes but in closer prox- 
imity to the sea. 
