DIVISION RHODOPHYTA 



In this division the cells contain a variety of pigments, chlorophyll, 

 phycocyanin, and phycoerythrin. The latter, a red pigment, is 

 usually predominant, especially in the marine forms, but varying 

 amounts of this and the other pigments produce violet, gray-green, 

 or blue-green colors. This is especially true for the fresh-water 

 Rhodophyta which are almost any color except red. The chromato- 

 phore, usually axial, contains a central pyrenoid which collects 

 starch as a food reserve. In one of the subgroups the end walls of 

 the cells have a pore which permits intercellular cytoplasmic con- 

 nections. 



The primary distinguishing characteristics of the division are the 

 structure of the sex organs, the sexual methods of reproduction, and 

 the types of life history entailed. 



Throughout the division the range of plant forms discloses an 

 evolutionary series which has counterparts in other algal groups. 

 There are unicellular, palmelloid, simple and branched filamentous, 

 and frond-like expressions. In the higher forais there is often found 

 considerable differentiation among the cells to form what might be 

 regarded as tissues. 



The majority of the Rhodophyta are marine, but a few genera 

 are either fresh-water or have representatives in inland habitats. 

 Many of these are found in streams in alpine or subalpine situations. 



There are 2 subclasses, the Bangioideae and the Florideae. The 

 former, which is the more primitive, contains 3 families in fresh 

 water. The Florideae, a much larger group, includes the majority 

 of species and is represented by 4 families in fresh water, 



CLASS RHODOPHYCEAE 

 SUBCLASS BANGIOIDEAE 



In this group, the fresh-water members possess a thallus which is 

 a branched or unbranched filament, or a ribbon-like or plate-like 

 expanse one cell in thickness. The cell walls are thick and gelatinous 

 and often somewhat lamellate. Unlike some of the Florideae, plants 

 in this group do not have intercellular protoplasmic connections. The 

 chromatophore, which is axial and stellate, contains a single pyre- 

 noid. Pigmentation as described for the division. 



Asexual reproduction is by nonmotile spores. In the few known 

 cases of sexual reproduction, divisions of the vegetative protoplast 



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