WATER MOLD (SAPROLEGNIA) 



353 



which are not known to have a Ufe history of the type character- 

 istic of either of the other subdivisions. Their hfe histories so 

 far as they are known are imperfect. 



Phycomycetes (Alga-like Fungi) 



This group, as their name suggests, resembles the Algae, but it 

 is a large assemblage of plants which vary widely in both struc- 

 ture and habit. Some of them live 

 in the water and have zoospores 

 and sex organs similar to those of 

 the Green Algae, while some have 

 lost their water habits and nearly 

 all of their algal features. There 

 are three principal orders — Water 

 Molds (Saprolegniales), Downy 

 Mildews (Peronosporales) , and 

 True Molds (Mucorales). 



Water Molds (Saprolegniales). — 

 These are the Fungi showing closest 

 affinities with the Algae. In fact, 

 if some of them had chlorophyll, 

 they could scarcely be told from ^^ 304 _ ^ ^r^^^. Mold 

 some of the Green Algae. They (Saprolegnia) . ^, a fly affected 

 live in the water where they feed with Saprolegnia. The fuzzy ap- 

 upon the dead bodies of insects, pearance of the fly is due to nu- 

 fish, and tadpoles. Sometimes they ^b^dy^of ^h:^'"?^^^^^^^^^ 

 attack hvmg organisms, as the one projecting hyphae which 

 called Saprolegnia illustrates. 



Water Mold (Saprolegnia). — 

 There are several kinds of Water 

 Molds, but the one called Sapro- 

 legnia, shown in Figure 304, is a 

 very common one. Although com- 

 monly a saprophyte on the floating pierced the wall of the oogonium 

 bodies of dead organisms, it often and thereby enabled the sperms 

 attacks and kills young fish that to reach the eggs. 

 are confined in close quarters, on which account it is some- 

 times very destructive in fish hatcheries. This Fungus, since 

 it can live on both live and dead organisms, shows that there 



have 



formed zoosporangia. From the 

 zoosporangium at the right the 

 zoospores • are escaping. C, a 

 tip of a projecting hypha bearing 

 an oogonium containing a number 

 of eggs. D, an oogonium and an- 

 theridium, the latter of which has 



