HOW TO KNOW THE SEAWEEDS 



123a Thallus firm to soft, but not mucilaginous; cortex more compact 

 than the medulla and variously modified. Fig. 162. . . .Galaxaura 



Fig. 162. Galaxaura oblongata (Solander) La- 

 mouroux 

 A small upper part of a plant, X 1.2. This 



is one of several species found in the tropical 

 waters of Florida. Most of the species are cylin- 

 drical, but G. marginata (Solander) Lamour- 

 oux is flat. Most of the species show some 

 indication of banding, whether smooth Uke G. 

 oblongata or covered with assimilative fila- 

 ments (superficial hairs) Hke G. subverticillata 

 Kjellman. 



Figure 162 



123b Thallus soft, usually somewhat mucilaginous, at least in the vicin- 

 ity of branch tips; cortex formed of branched lateral fascicles of 

 branches from the medullary filaments. Fig. 163 Liagora 



Fig. 163. Liagora ceranoides Lamouroux 



A small upper part of a plant showing 

 the irregularly dichotomous branching habit, 

 X 1.3. This is one of several species which 

 may be found in the tropical waters of 

 Florida. Some of them become quite heav- 

 ily calcified so that lower parts are rigid, 

 although the tips may remain soft. The 

 genus is represented on our Pacific Coast 

 by a single species, G. californica Zeh, 

 which is common at Catalina Island, near 

 Los Angeles. 



Figure 163 



124 



