116 THE SAPROLEGNIACE^ OF THE UNITED STATES, 



AcTilya prolifera (JS'ees ab E.) DeBary ('52). 



111. : DeBary, '52, PI. VII, Figs. 1-28. 



DeBary, '81, PI. II, Pigs. 1, 2, and IV, 1-4. 



This is the commonest European species, but it is doubtful if it has been 

 seen in this country. Either it or the almost equally common A. DeBaryana 

 appears very frequently in cultures, there. It is clearly distinguished by the abund- 

 antly pitted walls of its oogonia, which resemble those of the next species, and by its 

 numerous and long antheridial branches of diclinous origin. Fungi reported under 

 this name in American catalogues have belonged probably to the next or to other 

 species. 



From the fact of its abundance this species is rather more likely than any other 

 to have been the one which Nees studied and called A. prolifera, although we have 

 no means of knowing if this is actually the case. Under these circumstances there 

 was no obligation to continue the name, but DeBary has chosen to do so by restrict- 

 ing it to this species ; and, since it is the first name applied to the species, definitely 

 recognized as such, and has been applied to no other i-ecognizable species, it must 

 stand. It is true that DeBary did not clearly characterize the species in the modern 

 sense until 1881 ; yet in his earlier paper ('52) he described the pitted — or, as he 

 then thought, perforated — walls of the oogonium; and as this is the only known 

 European Achlya of that character, his description sufficiently marks the species, and 

 the earlier date should be quoted for it. 



Achlya Americana sp. nov. 



111. : PI. XVin, Figs. 69-73 (also on Pis. XIV-XVI). 



Hyphse stout, not very long. Zoosporangia very abundant, rather short and 

 thick, slightly fusiform. Oogonial branches short, erect, raceraosely arranged on 

 the liyphse. Oogonia terminal and globular, or rarely intercalary, their walls much 

 pitted, Antheridial branches numerous, branching, arising from the main hyphae 

 between and near the oogonial branches. Antheridia very numerous, cylindric or 

 somewhat clavate. Oospores from one to fifteen in an oogonium, usually five to nine, 

 excentric, their average diameter about 22;^. 



Massachusetts — Amherst : Pennsylvania — Philadelphia, Keller .■ Alabama — 

 Auburn, AtJcinson: Louisiana — St. Martinville, Langlois. 



It is rather remarkable that our most abundant member of this genus, and indeed 



