HOW TO KNOW THE SEAWEEDS 



56b Thallus monostromatic at the margins and of more than one cell 

 in thickness in older mid-parts and lower parts, reddish in color; 

 growth marginal; reproductive organs scattered over the blades 

 in small circular or elongate spots. Fig. 87 MyriogTamine 



Fig. 87. Myriogiamme spectabilis (Eaton) Kylin 



A single forked blade of a tetrasporangial 

 plant showing the elongated tetrasporangial 

 sori, X 0.6. This is our largest and common- 

 est species of Myriogramme. It normally grows 

 below low tide level along the California coast 

 and is to be looked for in beach drift. There 

 are several other localized species on the Pa- 

 cific Coast. 



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Figure 87 



57a Thallus 2 cells thick. Fig. 88 A Ulva 



57b Thallus 1 cell thick. Fig. 88 B Monos^roma 



Fig. 88. Transections of Ulva 

 (A.) and of Monostioma (B.) to 

 show different appearance of 

 monostromatic and distromatic 

 structure. 



A considerable number of spe- 

 cies of each of these genera oc- 

 curs both on the Atlantic and 

 Pacific coasts. The species are 

 widespread and in many cases 

 cosmopolitan. The best means of 

 identifying our Pacific species at 

 present is found in the volume 

 by Setchell and Gardner, 1920, while Taylor, 1937, treats most of the 

 Atlantic species. All of the members of each of these genera are thin, 

 expanded, membranous plants varying in size from a centimeter or 

 two up to more than two meters. In form they resemble the Porphyra 

 plant shown in Figure 86. 



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B 



Figure 88 



71 



