THAXTER. — ARGENTINE LABOULBENIAI.ES. 183 



Corethromyces Platensis nov. sp. 



Perithccium becoming translucent amber-brown; usually straight, 

 subconical, tapering more or less from the variably swollen venter to 

 the blunt hyaline apex; the tip more or less clearly distinguished above 

 a slight enlargement; the basal cells rather large; the stalk-cell 

 variably, often greatly, elongated, and tapering somewhat to its 

 insertion. Appendage consisting primarily of three superposed cells; 

 the basal, and sometimes also the others, more or less deeply l)lack- 

 ened; the subbasal cell bearing distally from its inner side a pair of 

 antheridial branches, one or both of which often become more or less 

 highly de\eloj)ed through monopodial branching, forming two main 

 axes of obliquely superposed cells; the lowest producing on the inner 

 side fan-like antheridial branches, the ultimate branchlets consisting 

 of two or three superposed antheridial cells; the rest bearing externally 

 simple or branched, sterile, upcurved, appressed branchlets, the lower 

 mostly blackened: the third cell of the primary appendage variably 

 developed; often very small bearing distally and from its inner face, 

 which may become outcurved and recurved, a variable numl)er of 

 simple bristle-like black branches, the lowest external one originally 

 terminal (usually broken off), one of the others often greatly developed 

 by successive monopodial branching, replacing the main appendage 

 and consisting of from three to twelve obliquely superposed cells, 

 each of which bears distally and externally, usually simple branch- 

 lets, for the most part short, three-celled, becoming more or less deeply 

 suffused with black or blackish brown, upcurved, more or less closely 

 appressed; the two or three uppermost hyaline, long, multiseptate. 

 Basal and subbasal cells of the receptacle hj^aline, small, subequal, 

 or the subbasal larger. Perithccium, including basal cell-region, 

 118-125X34-40^1, the sporiferous part 75-100 /x; the stalk-cell 

 40-60X 12-20 M. Spores 24X2.5 m- Greatest length of whole ap- 

 pendage 150-360 yu. Receptacle, including foot, 40X20 ju. Total 

 length to tip of perithccium 85-235 n. 



var. gracilis nov. var. Perithccium and its stalk-cell longer and 

 more slender than in the type. Appendage divergent, slender, its 

 primary axis consisting of three superposed cells; the basal hyaline 

 below, blackened and slightly constricted above; the subbasal hya- 

 line, rarely externally suffused, nearly twice as long as the basal cell, 

 a small cell separated from its inner distal angle forming a rounded 

 prominence from which arise right and left paired antheridial bran- 

 ches, wholly hyaline, spreading, several times closely Ijranched; an- 



