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THE AM ERIC AX XA TURALIST. [Vol. XXXV 



In the introduction the authors divide the entire west coast into 

 four quite well marked regions of algal growth ; the Tropical, the 

 North Subtropical, the North Temperate and the Boreal ; with the 

 suggestion that further study may make it necessary to divide 

 the latter into an Upper and a Lower Boreal. The approximate 

 boundaries are Magdalena Bay, Lower California ; Point Concep- 

 tion, California, and Puget Sound. The present work includes 

 such of the Temperate element as appears in Puget Sound, and the 

 whole of the Boreal. The subtropical families Valoniacese and 

 Dictyotacea; are each represented by a single species. If the divi- 

 sion of the Boreal into upper and lower is adopted, each of these 

 regions corresponds to a range of surface temperature, there being a 

 variation of 5 C. as we pass from one to another; each region 

 having approximately a difference of 5 C. between the maximum 

 and the minimum. The division between the upper and the lower 

 Boreal has an isochryme of 5 C. and an isothere of io° C. the 

 southern limit of the North Temperate having 20 C. and 25 C. 

 respectively. 



As is to be expected from the latitude, the great Laminariacea; are 

 the most conspicuous element of the Flora; this region probably 

 exceeds all others in the gigantic size of the individuals and the 

 variety of forms of this family. The genus Alaria is represented by 

 eighteen species and forms, one of which, A. fistulosa, has a blade 

 reaching a length of 25 meters. The eighteen different genera of 

 Laminariaceae form a very rich representation of the family. Litho- 

 thamhion and the allied genera are well represented, comparing fav- 

 orably with other northern regions; while the jointed Corallinacea; 

 have many forms, contrasting strongly with the single species found 

 on our Northeast coast. 



While many individual collectors at various points have contributed 

 to this work, the greater part of the material on which it is founded 

 was obtained by the expedition from the University of California, in 

 the summer of 1899, on which Professor Setchell was accompanied by 

 W. L. Jepson, L. K. Hunt and A. A. Lawson ; while it is certain that 



character of the marine Flora may be considered as fairly well estab- 



The arrangement follows the system of Engler & Prantl in the 



