Classification, 129 



*** Zoogonidia naked while in tlie zoosporangia, 

 becoming invested with a membrane after their 

 escape. 



Achlya. Zoogonidia arranged without order in the 

 zoosporangia ; oogonia polysporous. 



AphanomycGs. Zoogonidia arranged in a uniseriate 

 manner in cylindrical zoosporangia; oogonia uni-^, 

 bisporous. 



B. Zoosporangia arranged in a seriate manner ; 

 antherozoids formed from protoplasm of antheridia. 



Monohlepharis. Zoogonidia nniciliate. 



Leptomitus, Agardh. 



Hyphas constricted at regular intervals, sparingly 

 branched ; zoosporangia formed from the terminal 

 portions of the branches, one or several superposed ; 

 zoogonidia maturing within the zoosporangium and 

 not escaping until after germination. 



Leptomitus, Agardh, Syst. Alg. p. 50 ; Sacc. Syll. 

 vii. p. 2d5. 



Closely allied to the genus Saprolegnia, and dis- 

 tinguished chiefly by the hyphse being constricted at 

 regular intervals. 



Rhipidium, a genus not known in Britain, agrees 

 with Leptomitus in the constricted filaments, but is 

 distinguished by the flabellately arranged branches. 



Leptomitus lactens, Ag. 



Forming tassel-like waving tufts, attached at the 



base, dirty white and slimy ; filaments up to 5 cm. 



long and 6-12 fx thick, constricted at intervals, 



dichotomously branched, flaccid ; zoosporangia ter- 



K 



