174 Plant Biology 



water, securing foods from dead plants or animals. A few species cause 

 serious damage by parasitizing fish, amphibia, turtles, etc. Goldfish in 

 aquaria are frequently affected by the white mycelia of water molds. 



In Saprolegnia (Fig. 64) the hyphae are branched and the tips bear 

 enlarged zoosporangia (zo o spor -an' jia) (Gr. zoon, animal; sporos. 



E6GS 



OOGONIUM 



ANTHERIOIAL 

 TUBE 



ANTHERIOIUM 





Fig. 64. — A common water mold (Saprolegnia) of the class Phycomycetes. 

 Left, reproduction by asexual, motile zoospores; right, sexual reproduction by 

 gametes produced in antheridia and oogonia. The antheridia form antheridial 

 tubes through which the male gametes pass. (From Fuller and Tippo; College 

 Botany, Henry Holt and Company.) 



spore; anggeion, vessel). The hiciliated zoospores (swarm spores) lib- 

 erated by the zoosporangia swim ("swarm") in the water, then lose the 

 cilia, and surround themselves with a wall. Each of these gives rise to 

 many more zoospores, each of which germinates to form a new hypha. 



