HOW TO KNOW THE SEAWEEDS 



118a Thallus composed of filaments (Fig. 155), moderately calcified. 

 Fig. 156 Udotea 



Fig. 155. Udotea sp. 



The lower part of a small, delicate, 

 exotic species in which the filamentous 

 structure is evident, X 21. 



Figure 155 



Figure 156. Udotea ilabellum (So- 

 lander) Howe 



An entire plant, X 0.7, showing 

 the fan-like form, the concentric 

 lines of growth and the sand- 

 penetrating holdfast. This species 

 may be found in quiet waters 

 from North Carolina southward. 

 Other species are confined to 

 Florida within our territory. 



Figure 156 



119 



