1915 Muenscher ; on Algal Associations 75 



PHAEOPHYCEAE 



57. Cystophyllum geminatum* 71. Laminaria bullata* 



58. Fucus evanescens* 72. Laminaria saccharina 



59. Alaria sp.* 76. Leathesia difformis 



64. Nereocystis luetkeana* 78. Desmarestia ligulata herbacea* 



65. Agarum fimbriatum* 79. Desmarestia aculeata 



66. Costaria costata* 80. Soranthera ulvoidea 



68. Cymathaere triplicata 83. Colpomenia sinuosa 



69. Hedophyllum sessile 84. Coilodesme californiea* 



70. Hedophyllum subsessile* 



CHLOROPHYCEAE 



87. Codium nucronatum* 97. Ulva lactuca* 



90. Cladophora arcta* 98. Entermorpha linza* 



Vegetation in Lagoons 



Along the shores of San Juan Island there are a number of small 

 lagoons. The conditions for plant life in these lagoons are much dif- 

 ferent from those along the shore line, so that they possess a somewhat 

 characteristic vegetation. A number of these lagoons were examined, 

 and, as previously observed by Chambers (3), the water becomes quite 

 warm when the tide goes out. These pools are connected with the main 

 body of water by a tide stream through which the water runs in and 

 out, depending upon the direction of the tide {Plate 15). The vege- 

 tation of the warm pools of the lagoons is very different from the vege- 

 tation of the swift-running tide streams connecting them with the main 

 body of water (Table 15). 



The 'distribution of species in a typical lagoon is shown in Plate 15. 



