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The Filamentous Algae (continued).
Oedogonium: Zoospore Formation.
The green filamentous alga Oedogonium is something of an oddity amongst the members of the green algae (Chlorophycaea) for the unique and complex nature of its sexual and asexual modes of reproduction. It reproduces asexually in two ways.
The vegetative process involves the cell division of special "cap cells" resulting in the elongation of the filament. The other asexual process involves the production of motile zoospores and is shown in the pictures below.
Click for a diagram of Oedogonium.
Cladophora and Microspora.
The filamentous alga Cladophora is a common inhabitatant of freshwater locations. It is called blanket weed in some places -- not an inappropriate name when in late summer dense floating rafts of Cladophora can be found both at the pond's edge and in the open water, buoyed up with the oxygen generated by its own photosynthesis.
Unlike Spirogyra, Cladophora is capable of branching, and seems to produce little or no mucilagineous secretion. This, and the fact that salts tend to crystallize on the filaments of older specimens, gives it a rougher, grittier feel than other filamentous algae. It is also more readily colonized by epiphytic diatoms and other algae, and provides a protected foraging environment for the smaller pond creatures such as protozoa, worms, small crustaceans and insect larvae.
Its springiness also makes it more difficult to prepare the thin, flat specimens required by the microscope.