600 



APPENDIX A 



The Green Algae (Chlorophyceae) include unicellular and colonial motile forms 

 that swim by means of flagella or cilia, and also nonmotile types (Figs. 13.11 and 

 12, 26.4, 32.8 and A. 2). The latter range from single cells of various forms to 

 cell colonies that may be spherical, leaflike, or filamentous in form. Most of the 

 green algae are actually greenish yellow in color, because of the presence of a 

 yellow pigment in addition to chlorophyll. Some of the motile forms have a red 

 or brown pigment spot that is sensitive to light, called the eyespot. 



Fig. A. 2. Various desmids (green algae) . (From Hill, Over holts and Popp, Botany, 2d ed.) 



The members of this group are largely inhabitants of fresh water, though some 

 live in damp terrestrial situations. In many respects the green algae resemble the 

 higher plants and differ from the blue-green algae. Among the characters that 

 the green algae share with the higher plants are cells with distinct nuclei, chloro- 

 phyll that is apparently identical and similarly contained in chloroplasts, a 

 cellulose cell wall that is structurally similar, and starch instead of glycogen 

 produced as a food reserve. 



The Diatoms (Bacillariophyceae) have already been discussed in some detail 

 in Chap. XXVI. They are unicellular algae (Figs. 26.7 and A.3) with definite 



