SUB-CLASS IV 



RHODOPHYCE^E, OR FLORIDE^E 



THE Rhodophycece or red Algae are, in almost all 

 cases, seaweeds. A few genera (Batrachospermum, 

 Lemanea, Tuomeya, and Balbiania) belong to fresh - 

 waters exclusively, where they occur for the most 

 part in running streams, while a few other genera 

 (Chantmnsia, Uildbrandtia, Caloglossa, and Bostrychia) 

 have representatives in both fresh-waters and the sea. 

 The thallus is always multicellular, of very diverse 

 forms, and is composed of branching cell-filaments, 

 either separate and free or congenitally united in 

 their development. This union is effected in some 

 cases by a merely gelatinous envelope, but is gener- 

 ally brought about by a very tenacious intercellular 

 substance which binds the filaments so closely that 

 the whole body becomes parenchymatous in appear- 

 ance. The filaments increase in length by apical 

 growth, only the terminal cell dividing. This cell is 

 sometimes larger than the others, and sometimes 

 indistinguishable from them in size. Intercalary 

 growth takes place only by the extension of the 



