WITH IS^OTES ON OTHER SPECIES. 147 



Figs. 78-81. Achlya polyandra. 



Fig. 78. A sporangium with empty spore-membranes. X 300. 



Fig. 79. Ad oogonium on a strongly recurved branch, showing the separation of oosphere origins, with two antheri- 



dial branches. X 300. 

 Fig. 80." A young oogonium, with much divided antheridial branches. X 200. 

 Fig. 81. Details of oogonium and antheridia. X 540. 



Plate XIX. 



Figs. 83-86. Achlya apiculata. 

 Fig. 83. Two sporangia. X 200. 



Fig. 83. A young oogonium with three antheridia. X 300. 

 Fig. 84. An unusually recurved oogonial branch. X 300. 

 Fig. 85. The more typical lorm of oogonial branch. X 300. 

 .Fig. 8G. Details of a small oogonium with two antheridia. X 540. 

 Figs. 87-89. Achlya oblongata. 



Fig. 87. Hypha with sporangium and apical and lateral oogonia, antheridia omitted. X 74. 

 Fig. 88. Hypha with several racemosely arranged oogonia, tending to a pointed form. From Louisiana. X 74. 

 Fig. 89. An oogonium with several antheridial branches. X 200. 

 Figs. 90, 91. Achlya oblongata, var. globosa. From Alabama. 

 Fig. 90. An oogonium showing the oospores grouped at one side. X 300. 

 Fig. 91. Details of sexual organs, x 200. 

 Figs. 93-95. Achlya racemosa. 

 Fig. 92. A sporangium, x 200. 



Fig. 93. An oogonium with a single anlheridiuoi. X 200. 



Fig. 94, Details of sexual organs of the commonest form, with two antheridia. X 540. 

 Fig. 95. Two oospores, showing centric structure, x 540. 

 Figs. 96-98. Achlya racemosa, var. stelligera. 

 Fig. 96. A joung oogonium, with three antheridia. X 200. 

 Fig. 97. An oogonium with a single very small antheridial branch. X 200. 

 Fig. 98. Details of sexual organs, x 540. 



Plate XX. 



Figs. 99-102. Achlya papulosa. 



Fig. 99. An hypha with a sporangium and an oogonium. X 200. 



Fig. 100. A terminal and an intercalary oogonium, with antheridial branches. X 200. 



Fig. 101. A strongly apiculate terminal oogonium. X 200. 



Fig. 103. A terminal oogonium with a single antheridial branch. X 540. 



Figs. 103, 104. Achlya cornuta. 



Fig. 103. Three oogonia trom the same hypha, one strongly apiculate. X 350. 



Fig. 104. A three-sporcd apiculate oogonium. X 350. 



Figs. 105-107. Aphanomyces Imvis. 



Fig. 105. Two oogonia from one hypha, with antheridia of diclinous origin. X 540. 



Fig. 106. An oogonium thickly invested by antheridia. X 540. 



Fig. 107. A young oogonium with antheridial branches of androgynous origin. X 540. 



Figs. 108-111. Aphanomyces scaber. 



Fig. 108. An oogonium of the rough form of the species, on a short, lateral branch. X 540, 



