104 THE SAPKOLEGNIACEJE OF THE UNITED STATES, 



Saprolegnia monoica Pringsh. ('57). 



Syn. : S.ferax Auct. p. p. 111. : Pringsheim, '57, PI. XIX, XX. 



S. dioica Vnngsh. ('60). Reinke, '69, PI. XII. 



Diplanes saprolegnioides Leitgeb. ('68). DeBary, '81, PI. V, Figs. 11-19; VI, 1. 2. 



AcJilya intermedia Bail ('60a), sec. Lindstedt ('72). Ward, '83, PI. XXII, Figs. 17-22. 



Rothert, '88, PI, X, Figs. 14. 



PL XVr, Figs. 37-39. 



HjphsB rather stout, often long. Zoosporangia cylindric-clavate. Oogonia ter- 

 minal or rarely intercalary, usually on short lateral branches, globular, their walls 

 abundantly and prominently marked with large pits. Antheridia long-cylindrical, 

 uniting with every oogonium, on rather stout branches of androgynous origin, which 

 usually arise from the main hypha near the oogonial branch. Oospores commonly 

 not above ten, i-arely numerous, centric, their average diameter about 26//. 



Massachusetts — Cambridge, Trehase ; Amherst: Alabama — Auburn, Atkinson. 

 Europe. 



This species, obtained by Prof Trelease at Cambridge in 1881, was first pro- 

 cured by the writer from a pool containing dead Carex leaves, which bore abundant 

 masses of Ghoitophora / and subsequently from a mass of dead leaves and slime at 

 the bottom of a ditch draining cultivated fields. Among cultures from the Southern 

 States, it has appeared only once. It does not, therefore, seem to be very abundant 

 with us ; but it is well distinguished by the large and numerous oogonial pits and the 

 abundant and well-developed antheridia, which are lai-ger and more conspicuous than 

 those of any other species of the genus, except possibly 8. asterophora. 



The observation of the diplanetism of the zoospores of this species led Leitgeb 

 to establish a new genus, Diplanes, for it, although the phenomenon had previously 

 been observed in species of this genus. Lindstedt gives AcTilya intermedia Bail as 

 a synonym of Diplanes saprolegnioides Leitg., and is followed by Saccardo ('88). 

 Having been unable to examine Bail's description and figure, I must be content with 

 followins: the authors mentioned. 



'i-> 



Yar. montana DeBary ('88.) 



Differs from the type in its slightly or not at all pitted oogonia, on longer 

 branches. It has not been recognized in America. 



Saprolegnia spiralis Cornu ('72.) 



This form, which appears to have been recognized only by its author, is said to 

 differ from S. monoica chiefly in its longer oogonial branches, which are coiled in a 



