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BOTANY. 



Vaucheria. 



Sexual organs 

 differentiated. 



Synopsii. 



Vegetative stage ; branched threads, continuous, growth con- 

 fined to the ends of the threads and ends of the branches. 

 Sexual stage ; fertilization of an egg by a minute sperm nu- 

 cleus. 



Antheridium (male organ). Contains num- 

 bers of small spermatozoids. 

 Oogonium (female organ). Contains one egg. 

 Result of fertilization is the formation of a fertilized egg 

 (oospore), which after a period of rest grows into the vau- 

 cheria plant again. 



Material. — Freshly collected material of one of the species of vaucheria 

 which is in fruit. It can be obtained from the water of ponds or ditches, or 

 it is very often found growing on soil of pots in greenhouses. If preferred 

 it may be collected in advance and be preserved in 2% formalin, or it may 

 be purchased of supply companies. 



Microscope, etc. 



