[393] THE AI.GM 157 



of the north Atlantic. Furthermore, of the 126 species, 39 are 

 reported from Bering Sea, and of these, 18 are circumpolar or 

 north Atlantic forms and 21 are peculiar to the Pacific coast of 

 North America. 



At least three distinct regions may be distinguished in the 

 algal flora of the Pacific coast of North America ; a southern, 

 a Californian, and a northern. 



The southern region extends from Point Conception south- 

 ward, perhaps to the equator. It is characterized by Nereo- 

 cystis giganteus, Sargassum agardianum, Taonia lennebackera, 

 Zonaria tournefortii and many other tropical species. 



The Californian region extends from Point Conception on 

 the south, to Puget sound on the north, and is characterized by 

 forms like Dictyoneuron, Postelsia, Laminaria sinclairii. Lam- 

 inar ia andersonii, and Fucus harveyanus. It may more 

 properly be limited on the north by the mouth of the Columbia 

 River and the shore line between that point and Puget Sound 

 may be regarded as a transitional area. 



The northern region begins at Puget Sound and extends 

 northward to and including Bering Sea. It is characterized by 

 such species as Odonthalia aleutica, Polysiphonia bipinnata, 

 Euthora cristata, Rhodymenia -pertusa, Constantinea rosa- 

 marina^ Fucus evanescens megacephalus , Agarum turneri, Cy- 

 mathere triplicata, Laminaria bongardiana^ Laminaria bul- 

 lata, Dictyosiphon fceniculaceus , and Myelophycus intestinalis. 



