WITH NOTES ON OTHER SPECIES. 103 



Subfamily SajJ^^olegniece. 

 Saprolegnia IS'ees ab Esenb. ('23). 



Syn. : ? Conferva piscium Schrank (1789). 

 Conferva ferax Gruith. ('21). 

 S. molluscorum Nees ab Esenb. ('23). 

 Leptomitus clavatus Ag. ('24) . 

 " ferax Ag. ('24). 



" piscidieola Berk. ('3S). 



Achlya prolifera Auct. 

 Exsic. : Myc. Univ., 1213 (S. ferax). 



Algues de la France, 1195 (do.). 



HyphsB rathei- stout or slender, often not much branched. Zoosporangia formed 

 from their tips, generally cylindrical or slightly clavate, rarely short and in series ; 

 the later ones arising within the empty membranes of preceding ones by upward 

 growth of their basal walls, or rarely beside them by cymose branching. Zoospores 

 diplanetic, at first pyriforra, with two apical cilia, escaping by a usually terminal 

 mouth at the apex of a distinct papilla, and swarming separately ; after encystment 

 and rest becoming reniform swarmers with two lateral cilia ; finally encysting again 

 and germinating. Oogonia terminal or intercalary, never wholly filled by the one or 

 more oospores. Antheridia wholly absent in some species, and always present in 

 some. 



Key to recognized Species. 



a. Ocigonial wall always smooth and unpitted ; oospores excentric S. anisospora. 



Oogonial wall pitted, at least in some specimens ; oospores centric 6. 



Obgonial wall spiny ; oospores centric i. 



b. Oogonia in moniliform series, early falling apart, not all pitted S. monilifera. 



Oogonia not separating from the plants before maturity, all more or less pitted c. 



c. Antheridial branches attached to every oogonium d. 



Antheridial branches attached to some or to none of the oogonia ./. 



d. Plants diclinous ; pits small S. diclina. 



Plants androgynous ; pits large e. 



e. Oogonial branch short and straight S. monoica. 



Oogonial branch usually helically coiled S. spiralis. 



f. Antheridial branches often developed S. mixta. 



Antheridial branches very rarely or never developed g. 



g. Antheridium formed just below the oogonium, on the same branch S. hypogyna. 



Antheridia not developed, or very rarely so h. 



h. Oogonia irregular, often in torulose series, with few and small pits S. touulosa. 



Oogonia globular, or not rarely cylindrical, not in series, with large pits S. ferax. 



i. Oospores one or two in an oogonium ; hyphaj slender S. asterophoka. 



Oospores several in an oogonium ; hyphae very stout > S. Trele.\seana. 



A. P. S. — VOL. XVII. N. 



