46 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



A few other species exhibit a marked predilection for proximity to 

 the sea without bein«r apparently either sand-loving or salt-loving 

 plants. Such are : 



Artemisia siihsttorfli. Poa iHichi/pholig. 



CahniKiinostix atvutica. Polinxxliuni scnulrri. 



Hydasti/hts horrulifi. .S'o//>r hoohcriuna. 



Hydantijlus hrarhypus. Sclaginella 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 liuppia marit'una occurs in brackish 

 waters. 



SPHAGNUM BOOS. 



Sphagnum bogs are quite counnon throughout western Washington. 

 The usual shrubs are Labrador tea {Ledum latifoliuni), laurel {Kal- 

 mia f/iauca), and cranlx?rry {Oxycoccus oxycoccus mtermediiis). 

 Usually a Avillow {Salix myrtilloides) , sweet gale {Myr'tca <jnle)^ and 

 a dwarf birch {Betula f/land ulotta) are present also. On the drier 

 hummocks small hendocks {Tsuga 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 

 rotundi folia), cotton-grass {Eriophonun inisaeolum) , Scheuchzeria 

 palustrifi, and Jvncus oj'eyana. 



In the bogs near the ocean coast Ledum columhianum and Myrica 

 calif omica 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 i)eculiar. 

 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 Artie 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. 



