WITH NOTES ON OTHER SPECIES. 



85 



These ideas concerning the relationships of the genera may be graphically 

 expressed as follows : 



8. Aplanes. 



7. Dictyuchus. 



G. Thraustotheca. 



" Dictyosporangium." 



4. AcMya. 



5. Aphanomyces. 



3. PytMopsis. 



2. Leytolegnia. 

 ]. Sajprolegnia. 



Sexual Repeoductioit. 



The reproductive organs of the second class are morphologically sexual, 

 though, as will be seen later, they are not physiologically so in all cases. In the fol- 

 lowing account they will be described as sexual organs without reference to the occur- 

 rence of a definite sexual act, which will be subsequently discussed. Since they are 

 the morphological equivalents of the truly sexual organs of related fungi, there is no 

 occasion to change the names which they received when believed to be also their 

 functional equivalents. 



All of the described species of Sajjrolegniece produce sexual organs, usually 

 after the maximum development of sporangia has been passed ; indeed it is impos- 

 sible to distinguish the species except by their sexual organs. !N^one of the Lepto- 



