128 THE NORTH AMERICAN SLIME-MOULDS 



species stand rigidly erect The sporangia vary in form and 

 in the branching of the columella. In the more globose phases, 

 the columella almost always shows a peculiar dichotomy near 

 the apex ; in the cylindric types, this peculiar division fails. 

 In fact, the shape is determined by this peculiarity of branching 

 as affects the columella. 



The species in this country has received various names, but 

 so far as can be determined, all apply to the same thing, and 

 comparison of specimens from Mr. Ellis with those from Europe 

 show the correctness of the nomenclature here adopted. 



5. COMATRICHA NiGRA (Pers.} ScJiroeter. 



PLATE XI., Figs, i, 2, 3. 



1791. Stemonitis nigra Pers., Gmel., Syst. Nat., p. 1467. 



1801. Stemonitis ovata, var. nigra Pers., Syn., p. 189. 



1863. Stemonitis friesiana De By., Rab. Eur. Fung., No. 568. 



1875. Comatricha friesiana (De By.) Rost., Mon., p. 200. 



1889. Comatricha nigra (Pers.) Schroeter, Pilz. schles., I., p. 118. 



Sporangia scattered, ferruginous or dark brown, globose or 

 ovoid, stipitate ; stipe long, hair-like, tapering upward, black ; 

 hypothallus none ; columella rapidly diminished toward the top, 

 at length dissipated ; capillitium of slender flexuous threads, 

 radiating horizontally, repeatedly branching and anastomosing 

 to form an intricate dense network, from the surface of which 

 project a few short hook-like peridial processes; spore-mass 

 black, spores by transmitted light dark violaceous, smooth or 

 nearly so, 7-10 yu,. 



This species is easily recognized by its almost globose spo- 

 rangia mounted on long slender stocks. These are 2 or 3 mm. 

 high and generally persist, as Persoon noticed, a long time after 

 the sporangium has fallen. The sporangia are at first black ; 

 after spore disposal pale ferruginous. In shape they vary from 

 ovate to spherical. Sometimes they are umbilicate below, so 

 that a vertical section would be obcordate. Care must be taken 

 to distinguish the present species from blown-out forms of 

 Lomprodcrma. 



