54 THE NORTH AMERICAN SLIME-MOULDS 



Sporangia gregarious, small, spherical, at first fuliginous 

 throughout, stipitate ; the peridium thin, destitute of lime, irides- 

 cent, breaking up and deciduous in patches, except at the base ; 

 stipe twice the diameter of the peridium, brown, fluted, not hol- 

 low, tapering upward from a small but distinct, radiant hypo- 

 thallus; columella none; capillitium dense, persistent, the nodes 

 frequently calcareous, elongate and vertical, especially below, 

 yellow ; spore-mass brown ; spores by transmitted light bright 

 violaceous brown, slightly papillose, 9-10 /z. 



This species is instantly distinguishable from all cognate forms 

 by its peculiar sooty color. Not less is the species structurally 

 marked by its capillitium. The latter below is exactly as in the 

 species of Tilmadoche. Indeed, the present species unites 

 characters supposed to distinguish Physarnm from Tilmadoche, 

 and would so far justify those authors who bring all the species 

 of both genera together under one generic name. In any case 

 the species is by its capillitium entirely distinct from P. galbenm, 

 as well as by the structure of the stipe and the peridial surface. 

 The plasmodium, at first watery, emerges from decayed elm 

 logs and soon takes on a peculiar greenish tint preserved some- 

 what in the mature fruit. 



Rostafinski, Monograph, pp. 105, 106, rejects Berkeley's 

 specific T&mQ, flavicomum, because it refers to the somewhat 

 indefinite characteristic, color. As this is no valid reason for 

 change, we have restored Berkeley's specific name, which by 

 general consent has priority. N. A. F., 3299. 



Not common. New Jersey, Ohio, South Carolina, Iowa. 



35. PHYSARUM NUCLEATUM Rex. 



1891. Physarum nucleatum Rex., Proc. Phil. Acad., p. 389. 



Sporangia gregarious, spherical, \ mm., white, stipitate ; perid- 

 ial wall membranaceous, rupturing irregularly, thickly studded 

 with rounded white lime granules ; stipe about i mm., subulate, 

 yellowish white, rugose ; columella none, capillitium dense snow- 

 white, with minute white round or rounded white nodes, in the 

 centre a conspicuous mass of lime forming a shining ball, not 



