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A TEXT-BOOK OF BOTANY 



Vaucheria produces very large asexual spores. The 

 tip of a branch becomes separated from the rest of the body 

 by a wall (Fig. 101, A). In this improvised chamber the 

 whole of the contents form a single large spore. It escapes 

 into the water through an opening in the wall, (Fig. 101, B) 

 and finally develops a new filament (Fig. 101, C). 



Sex organs (antheridia and oogonia) are also developed. 

 In a common form of Vaucheria they appear separately on 

 the side of the large coenocytic body, and are separated 

 from the general cavity by walls. The oogonium is a 

 globular cell (Fig. 102, 6), usually with a perforated beak 

 for the entrance of sperms (Fig. 102, /), and contains a single 



FIG. 102. Sexual reproduction in Vaucheria: A, a single antheridial branch with 

 an empty antheridium (a) at its tip, and also an oogonium (6) containing a 

 heavy-walled oospore (c) and showing the beak (/) through which the sperm 

 passed; B, another species, in which a single branch bears several oogonia, and 

 a terminal coiled antheridium. 



large egg. The antheridium is a much smaller cell, on the 

 end of a branch (Fig. 102, a), within which numerous very 

 small sperms are formed. The usual escape into the water 

 and entrance into the oogonium is followed by fertilization 

 (one sperm fusing with the egg), which results in an oospore. 

 The oospore develops a thick wall and is thus protected until 

 the next growing season (Fig. 102, c). In another species, 



