HOW TO KNOW THE SEAWEEDS 



153b Thallus thin, oi few cell layers, the surface cells little different 

 from those of the inner layers. Fig. 192, 193 Punctaria 



& 



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Fig. 192. Punctaria sp. 



Part of a transection of a blade 

 showing the relatively uniform cell 

 structure compared to Ilea, X 125. A 

 gametangium and two (?) sporangia 

 are shown. 



Figure 192 



Fig. 193. Punctaria plantaginea (Roth) Greville 



An entire young plant, X 0.5. This species, 

 and the somewhat more slender and delicate 

 P. latiiolia Greville, occur on stones or on algae 

 and Zosfera from New Jersey northward. On 

 the Pacific Coast four species occur between 

 central California and Puget Sound, Washing- 

 ton, but they are all of infrequent or geo- 

 graphically restricted occurrence. 



Figure 193 



149 



