CRYPTOGAMS 



189 



minate. The short floating filaments, often much stouter 

 than those of the Bread Mold, may be distinguished by 

 the naked eye. Under the microscope they are seen to 

 compose an unseptate branching mycelium, which pene- 

 trates the object upon which it grows. 



449. Reproduction. The more or less swollen ends of 

 some branches are seen to be filled with dense protoplasm 

 and to be cut off by 



septa to form the 

 zoosporangia (Fig. 

 308, A). The con- 

 tents finally breaks 

 up into numerous 

 rounded bodies which 

 finally escape from a 

 terminal opening in 

 the zoosporangium. 

 These bodies, the zoo- 

 spores, in some spe- 

 cies are motile from 

 the time they are set 

 free ; in other species 

 just after ejection 

 they surround them- 

 selves by a delicate 

 cell wall, from which 

 they soon escape and 

 swim away, soon to 

 germinate. 



450. Resting oo- 

 spores are formed 

 from egg cells, pro- 

 duced in spherical 

 oogonia (Fig. 308, 

 D), fertilized from 



antheridial tubes (Fig. 309), which penetrate the oogonial 

 wall in order to reach the egg cells. After fertilization 

 the Qpspore surrounds itself with a thick wall. 



. Water Mold: A, zoosporangium; B, es- 

 caped zoospores, before becoming motile ; 

 C, zoospores in the active stage; D, 

 oogonia and antheridia (a) . The lower 

 oogonium contains an unfertilized egg 

 cell (e), and two young oospores (o) ; the 

 upper shows four mature oospores (sp) . 



