THE MARINE FLORA OF 

 THE PACIFIC COAST 



BY WILLIAM ALBERT SETCHELL 



Professor of Botany, University of California 



THE marine flora of the Pacific Coast of North 

 America is a rather large topic to be considered 

 in four or five pages; consequently only salient 

 features can here pe spoken of, and but general 

 directions for obtaining acquaintanceship may be 

 given. The general heading of marine flora may be 

 taken to include the vegetation of the submerged 

 shore areas and of those maritime rocks or other 

 areas within the direct influence of the ocean. 



Along this extensive line of shore may be found, 

 so far as the marine flora is concerned, three or 

 four distinct temperature zones, namely, the Upper 

 Boreal Zone, including Bering Sea; the Lower Boreal 

 Zone, extending from Bering Sea south to the Straits 

 of Fuca or below, perhaps even to the mouth of the 

 Columbia River; the North Temperate Zone, from 

 Cape Flattery or the mouth of the Columbia River 

 south to Point Conception; the North Subtropical 

 extending from Point Conception south to Magda- 

 lena Bay or Cape San Lucas, south of which is the 

 Tropical Zone. Each zone has a flora the general 

 aspect, or facies, of which is distinct and charac- 

 teristic. Each temperature zone includes on the 

 west coast of North American one region. Each 

 region may be divided into districts, and the dis- 

 tricts according to varying physical characteristics, 

 into formations, such as reef, cliff, tide-pool, beach, 

 salt marsh, and others. For each formation there 

 are bathymetric or tidal zones, in which character- 

 istic plant associations may be found. 



The spermaphyte, or pnaenogamous element of 

 the marine flora, is limited to a very few species. 

 The genus Phyllospadix represents this element on 

 our exposed coasts and the genus Zostera in quiet 

 waters. Another genus of the Naiadaceae, namely, 

 Zannichellia is found in brackish waters, together 

 with Ruppia and one or two species of Potamogeton. 



Phyllospadix is characteristic of the west coast 

 of North America and contains two species, P. 

 scouleri and P. torreyi. They form the eel-grass 

 associations of rocky exposed formations, conspicu- 

 ous as patches of small extent where the surge or 

 currents are strong. P. scouleri withstands more 

 violence than does P. torreyi, has rather broader 

 leaves and seldom has more than one spadix, while 



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