Figure 6. The common green seaweeds (A) Ulva, and 

 (B) Enteromorpha. 



have broad flat blades with tubular 

 morphology only along the margins (i.e. 

 superficially like Ulva ) , some members of 

 this genus are difficult or impossible to 

 distinguish from Ulva without a 

 microscope. In culture, some Ulva species 

 produce tubular progeny, suggesting that 

 distinctions between the two genera are 

 questionable. Cladophora is one of the 

 most common genera of small green 

 filamentous algae. It can easily be 

 confused with a number of other algae by 

 nonspecial ists. The red alga Porphyra is 

 Ul va -1 ike in morphology but is usually 

 brown to purple in color. 



filamentous forms 

 Herposiphoni a , 

 Erythrotrichia are 

 difficult to 



The lower intertidal zone is usually 

 occupied by a mixed species group of red 

 seaweeds (Figure 5). Several small 

 such as Pol ysiphonia , 

 Audouinel 1 a , and 



common, but these are 

 identify without 



magnification. Hypnea musciformis is a 

 very common larger seaweed with bushy, 

 cylindrical branches that often end in 

 fish-hook like tendrils that are used to 

 attach secondarily to other seaweeds 

 (Figure 7). Like many of the red 

 (Rhodophyta) seaweeds, it may be deep 

 green, red, straw-colored, or some 



Figure 7. (A) The common red seaweed Hypnea 

 musciformis. Its hook-shaped branch tips often 

 facilitate its attachment to other seaweeds. (B) shows 

 a close-up of a Hypnea tip that has attached around 

 the base of a Sargassum float. 



10 



