52 THE MYXOMYCETES 



The appearance is very characteristic, unlike P. virescens in habit, 

 size and color. Colonies are quite often three inches in length. The 

 most common habitat seems to be rotten oak, especially fragments of 

 charred logs, etc. 

 Ohio, Illinois, Iowa, Missouri, Nebraska; Nigeria, South Africa. 



13. Physarum famintzini Rost. 



Mon. 107. 1875. 

 1898. Physarum gulielmce Penzig, Myx. Buit. 34. 



Sporangia sessile, subglobose or reniform, about 0.4 mm. in width, 

 brownish orange or chestnut brown, rugulose, clustered or heaped, 

 often with a yellow membranous hypothallus; peridium membranous, 

 with clustered deposits of yellowish brown lime granules; capillitium 

 abundant, the nodes angular, branching, white; spores purplish brown, 

 spinulose, 10-12 /jl. Plasmodium yellow or orange. 



This is an old-world species. In the United States National Herba- 

 rium there is a scanty collection from Maryland (No. 15976), consist- 

 ing of five sporangia, growing with Didymium squamulosum, which 

 must be referred here. The hypothallus is brilliant orange, the spores 

 purplish, 9-11 m, averaging 9.5/*, a little small for the species as 

 described. In other respects the agreement is perfect. 



Maryland ; Europe, Java. 



14. Physarum confertum Macbr. 



N. A. Slime-Moulds ed. 2. 64. 1922. 

 PL XXI, Fig. 560. 



1896. Physarum atrum Schw. ex Morg., Jour. Cin. Soc. Nat. Hist. 19 : 27, 

 non Schw. 



Sporangia subglobose or somewhat elongate, sessile, small, 0.2- 

 0.4 mm. in diameter, gregarious or confluent, often clustered or in 

 heaps, dull violaceous brown; peridium thin, more or less transparent, 

 nearly limeless, or reticulated or sprinkled with minute white flecks of 

 lime; capillitium scanty, the nodes small, elongate, rounded, white; 

 columella none, spores violet-brown, minutely warted, 10.5-12.5 ju. 

 Plasmodium white or yellowish. 



Following Morgan, this has frequently been referred to as P. atrum 

 Schw. The latter species is now known to be a limeless form of P. di- 

 dermoides. P. reticulatum Berl., in Saccardo, Syll. Fung. 7:350, 1888, 

 non Alb. & Schw., is based on P. atrum Schw. The species has also 

 been confused with P. cinereum, P. plumbeum and others, but it is in 

 fact quite distinct, distinguished from everything else by the color and 



