46 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
A few other species exhibit a marked predilection for proximity to 
the sea without being apparently either sand-loving or salt-loving 
plants. Such are: 
Artemisia suksdorfii. Poa pachypholis, 
Calamagrostis aleutiea. Polypodium scouleri, 
Hydastylus borealis. ° Salix hookeriana. 
Hydastylus brachypus. Selaginella struthioloides, 
In addition to these the marine aquatic genera Zostera and Phyl- 
lospadix deserve mention as our only genera of flowering plants 
found in the ocean. The related Ruppia maritima oceurs in brackish 
waters. 
SPHAGNUM BOGS. 
Sphagnum bogs are quite common throughout western Washington. 
The usual shrubs are Labrador tea (Ledum latifolium), laurel (Mal- 
mia glauca), and cranberry (Oxycoceus ovycoccus intermedius). 
Usually a willow (Salix myrtilloides), sweet gale (Myrica gale), and 
a dwarf birch (Betula glandulosa) ave present also. On the drier 
hummocks small hemlocks (7suga heterophylla) often occur, and in 
similar situations one is often surprised to find the black pine (Pinus 
contorta), typically a plant of barren, gravelly or sandy soil. 
The more interesting and characteristic herbs are sundew (Drosera 
rotundifolia), cotton-grass (Lriophorum russeolum), Scheuchzeria 
palustris, and Juncus oregana. 
In the bogs near the ocean coast Ledum columbianum and Myrica 
californica replace their two close relatives. 
THE COASTAL STRIP. 
One other important forest association of Washington, namely, the 
tideland or Sitka spruce forests, in immediate proximity to the Pacific 
Ocean, is perhaps best classed as Humid Transition zone rather than 
otherwise. The facts in the distribution of this species are peculiar. 
It is the dominant tree, forming over 50 per cent of the forest strip, 
along the coast from middle Oregon northward to Kadiak Island, 
beyond which all timber ceases, and the flora becomes almost that of 
the Artic Zone. Therefore we have this one species of tree dominat- 
ing a continuous stretch of sea level, from the Arctic Zone to the 
Humid Transition, through both the Hudsonian and the Canadian 
zones. In the north the Sitka spruce forests end sharply with the 
arctic meadows. In the south they merge imperceptibly with the 
red-fir forests. This enormous stretch of a single species at sea level 
is probably due to the remarkably equable temperature and great 
humidity of the immediate seacoast. 
