118 THE SAPROLEGlSriACE^ OF THE UNITED STATES, 



antheridial filaments of androgynous origin, but agrees very closely in other respects 

 with the two preceding species. As above indicated, it is the A. yolyandra of 

 DeBary, but it is clearly not the species to which that name was given earlier by 

 Hildebrand ('67). DeBary appears to have believed that his species was that intended 

 by Hildebrand; but, as will be fully shown later, this is not the case. And, since 

 Hildebrand's species was pretty carefully described, it is perfectly recognizable. 

 Hence the name A. jJolyandra belongs to it alone, and DeBary 's species is left with- 

 out a name. I therefore propose for the latter the name A.De Baryana, in honor of 

 the profoundest student of the Saprolegniaceae, to whom so large a part of our knowl- 

 edge of the family is due. 



ACHLTA ME&ASPEKMA Sp. UOV. 



111.: PL XVIII, Figs. 74-77. 



Hyphse stout, long. Zoosporangia thick, fusiform, freely developed. Oogonial 

 branches short and straight, racemosely arranged. Oogonia terminal, globular, with 

 smooth and unpitted walls which are strongly thickened. Antheridial branches often 

 arising near the oogonial branches, but apparently never from them, much branched, 

 often producing no antheridia. The latter absent from many oSgonia, from one to 

 several on others, short-clavate. Oospores two to eight, commonly four to six, in an 

 oogonium, centric, very dark when young, their average diameter 45//. 



Massachusetts — Amherst. 



Cultures from 8pirogyra, dead leaves, etc., taken from a boggy spot by a small 

 brook, are the only ones v/hich have yielded the present well-marked species. The 

 sporangia recall, in form and abundance, those of A. Americana, but the hyphse are 

 rather stouter and more vigorous than in that species. The very thick-walled 

 oogonia, often without antheridia, and the very large oospores, the largest known in 

 this family, sometimes exceeding 50,^ in diameter, distinguish it clearly from any 

 other form. The thickening of the oogonial wall is not perfectly even, but its inner 

 surface is somewhat irregular (Fig. 77) from unequal deposits of material. The pro- 

 toplasm of the young oogonia and the oospheres formed from it is very dense and 

 dark colored, surpassing in this respect even that of A. apiculata. The plant is 

 androgynous, but many of the smaller branches, which resemble in every other 

 respect antheridial branches and strikingly suggest those of A. DeBaryana, fail to 

 develop antheridia, and remain unattached to oogonia. Branches which do bear 



