30 THE NORTH AMERICAN SLIME-MOULDS 



charged with polygonal nodules of lime, yellow ; spore-mass 

 black ; the spores, by transmitted light, violaceous, warted, 

 globose, 10-13 /*. 



A very distinct species not likely to be confused with any- 

 thing else, although in description, so far as concerns external 

 characters, suggesting Cienkowskia reticulata. The two forms 

 are not at all alike when placed side by side. For details as to 

 the difference, see the description of the species last mentioned. 

 N.A. F., 1396. 



Apparently not rare in the eastern United States, Pennsylva- 

 nia, Virginia, Ohio, Iowa. 



In 1805, Albertini and Schweinitz, Conspectus Fungomm, p. 

 251, t. 7, Fig. 2, described as Physarum reticulation, an Eu- 

 ropean form which became the basis of Rostafinski's genus 

 Cienkowskia. (See under that genus.) Later, 1829, Schweinitz 

 discovered in America a Pfaysarum-looking specimen which 

 he took to be the same thing and accordingly placed in his her- 

 barium under this name and entered N. A. F., 2295. Rostafinski 

 further renamed another Schweinitzian species, Fnligo mnscorum, 

 calling it, Mon., p. in, Physarum gyrosum. Wingate and Rex 

 apply in Ellis, N. A. F., 1396, this latter name to No. 2295 

 of Schweinitz. Such reference is a mistake, judging from Ros- 

 tafinski's descriptions and from the description and figure of 

 Alb. and Schw. (Consp. Fung., p. 86, t. 7, i), and by the testimony 

 of Lister. Furthermore, Rostafinski's species is without foun- 

 dation, since what he describes appears to be a Fuligo, as Alb. 

 and Schw. first supposed. The name proposed by Morgan 

 is accordingly the first specific name accompanied by descrip- 

 tion and properly applied. 



4. PHYSARUM DIDERMA Rostafinski. 

 1875. Physarum diderma Rost., Mon., p. no. 



Sporangia clustered, snow-white, sessile or narrowly adnate 

 at base, globose or polygonal by mutual compression ; peridium 

 double, the outer more dense, fragile, thick, calcareous, the inner 

 delicate, remote, translucent; capillitium well developed, the 



