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TEXTBOOK OF BOTANY 



to end and always divide in the same plane, the plant is a single un- 

 branched filament. Each plant is attached to rocks or other objects by 

 a special holdfast cell (Fig. 281). The chloroplast is a green iDand of 



t 



^ 



V 



^' 



Fig. 281. Fresh-water algae. The upright filaments are, from left to right: 

 Oedogonium, producing motile spores, eggs, and sperms; Microspora, forming rest- 

 ing spores and motile spores; and Ulothrix, forming motile spores and gametes. 

 The horizontal filaments are Spirogyra (left) and Vaucheria (right). Highly 

 magnified. Courtesy of World Book Co. 



