148 THE SAPROLEGNIACE^ OF THE UNITED STATES, ETC. 



Fig. 109. Two oogonia on the same hypha, the lower abortive, the upper with an antheridium. X 540. 



Fig. 110. An oogonium of the smooth form of the species, with an antheridium. X 540. 



Fig. 111. An old oogonium, with a ripe oospore and no antheridium. X 540. 



Figs. 112-114. DictyucTius Magnusii. From Cambridge, Mass. 



Fig. 112. An empty sporangium showing some of the openings for the exit of zoospores ; from a slide by Prof. Tre- 



lease. X 200. 

 Fig. 113. An oogonium with single oospore and antheridial branch. X 500. 



Fig. 114. A young oogonium with antheridial branch. X 500. The last two after sketches by Prof. Trelease. 

 Figs. 115-118. Leptomitus laeteus. 



Fig. 115. An empty and a young sporangium, formed from successive segments of an hypha. x-^00. 

 Fig. 116. The same, showing also the peculiar branching below a sporangium. X 200. 

 Pig. 117. Zoospores encysted within a sporangium. X 200. 



Fig. 118. Encysted and germinating zoospores, and empty membranes pointing to diplanetism. X 540. 

 Figs. 119-121. Apodachlya completa. From Louisiana. 

 Fig. 119. Toung sexual organs. X 540. 

 Fig. 120. Adult sexual organs, with ripe oospores. X 540. 

 Fig. 121. Details of sexual organs, with peculiar structure in antheridial branches. X 940. 



Note.— All drawings are from specimens obtained at Amherst, Mass., except where the contrary Is noted. 



