156 Mycetozoa of North America 



Spores reticulate. 



Reticulate with spines; sporangia black, slender 



and very long, in large clusters. 16. C. longa 



Reticulate with raised bands; sporangia brown, 



sessile, small and in small clusters. 17. C. Rispaudii 



1. Comatricha nigra (Pers.) Schroet. in Cohn, Krypt. Fl. Schles. 

 3(1): 118. 1885. 



Stemonitis nigra Pers.; Gmel. Syst. Nat. 2: 1467. 1791. 

 Comatricha ohtusata Preuss, Linnaea 24: 141. 1851. 



Plasmodium watery white (Lister). Total height 1 to 8 mm. 

 Sporangia globose, ellipsoid, rarely short-cylindrical, scattered 

 or gregarious, size variable depending on the length of the stalk, 

 purplish brown; sporangial wall evanescent. Stalk subulate, 

 slender, shining, black, usually 2 to 8 times the length of the 

 sporangium in globose forms, shorter in cylindrical ones, rising 

 from a more or less distinct hypothallus. Columella usually 

 reaching almost to the summit of the sporangium, branching 

 above and continued into the capillitium. Capillitium a more or 

 less dense tangle of purplish brown threads springing from all 

 parts of the columella, anastomosing and branching, of nearly 

 equal thickness throughout, the ultimate branches looped and 

 showing few free ends or marked with short spine-like branchlets. 

 Spores violet-brown, minutely and closely spinulose, 7-10 /x diam. 



Var. alta (Preuss) Lister, Mycetozoa ed. 2. 152. 1911. 

 Comatricha alta Preuss, Linnaea 24: 141, 1851. 



Sporangia lengthened or cylindrical; capillitium a tangle of 

 long, flexuose threads attached chiefly by a few branches to the 

 base of the columella. 



Type locality: Germany. 



Habitat: On dead wood. 



Distribution: Common throughout North America; var. 

 alia, New York. 



Illustration: Lister, Mycetozoa ed. 3. pi. 123, figs. a-h. 



Accepting the basic, typical form of C. nigra as brown, having 

 globose sporangia on long stalks, a columella reaching nearly to 

 the apex, a dense capillitium, and spores faintly spinulose and 

 violet-brown in color, there are departures in different directions, 

 but with connecting forms, finally terminating in a group of well 

 marked centers which are considered as species, although inter- 

 mediates may occasionally be seen in developments of C. nigra. 



