HOW TO KNOW THE SEAWEEDS 



155b Cortex without gland cells 156 



156a Transection showing many of the medullary filaments running 

 from cortex to cortex and more or less perpendicular to the sur- 

 face of the blade. Figs. 196, 197 Halymenia 





r<n^A n^DQoDo 80Oo 



Fig. 196. Halymenia sp. 



Part of a transection of a tetrasporangial- 

 blade showing the medullary filaments 

 running from cortex to cortex, X 250. 



Figure 196 



Fig. 197. Halymenia gelin- 

 aria Collins & Howe 



Habit of a small plant, X 

 0.5. This is one of several 

 species which occur in infra- 

 tidal waters from North Car- 

 olina to Florida and which 

 are quite often encountered 

 in beach drift. All are broad, 

 rather thin plants of slippery 

 texture. One or more spe- 

 cies may also be found in 

 drift along the California 

 coast. Of these, H. californi- 

 ca Smith & Hollenberg may 

 be recognized by its cross 

 section and broadly falcate 

 (sickle-shaped) blades. 



Figure 197 



156b Transection showing few or no medullary filaments running from 

 cortex to cortex and perpendicular to the blade surface 157 



151 



