34 THE NORTH AMERICAN SLIME-MOULDS 



Sporangia sessile, crowded or heaped, spherical, ovoid or 

 elongate, yellow or greenish yellow ; peridium thin, fragile ; 

 capillitium delicate, with rather small, irregular, yellowish, cal- 

 careous nodes ; columella none ; spores bright violet, minutely 

 roughened, 7-9 ^. 



This beautiful species occurs more commonly on moss tufts, 

 with which it is frequently concolorous, or escaped upon dead 

 leaves, etc. The peridium is flecked with calcareous scales or 

 grains stained with yellow or green, and to these the whole fruit 

 owes its peculiar color. The color and aggregated, heaped 

 sporangia are distinctive macroscopic characters. 



The form described, Biill. Lab. A T at. Hist, fa., II., p. 158, as 

 P. anriscalpium Cke., is by Mr. Lister reckoned a variety of the 

 present species, var. nitcns. It differs chiefly in its larger 

 size, less calcareous peridium, solitary habit, and more purely 

 yellow color. The peridium is very thin, and tends to open by 

 a longitudinal fissure. The spores are similar in size and sur- 

 face, but the capillitium is remarkably different in the two 

 forms. For Physarum anriscalpium Cke., see No. 16 below. 



In the Monograph, p. 1 1 3, Rostafinski adopted properly Dit- 

 mar's name for this species. Upon later consideration, in the 

 Appendix, p. 8, he changed the name, writing P. ditniari, on 

 the ground that virescens was descriptive of a character to 

 which the species in question occasionally refuses to conform. 

 Most authors since Rostafinski have simply accepted his sug- 

 gestion, so that in recent literature the species is generally 

 entered P. ditmari Rost. P. virescens is certainly to be pre- 

 ferred. N. A. P., 2692. 



Canada, New England, New York, Pennsylvania, Ohio, 

 Iowa, Black Hills, South Dakota. 



10. PHYSARUM CINEREUM (BatscJi] Pcrs. 



PLATE IX., Figs. 4, 4 a, 4 b, and 4 c. 



1786. Lycopcrdon cinereum Batsch, Elench. Fung., p. 249, Fig. 169. 



1805. Physarum cinercnm Persoon, Synopsis, p. 170. 



1829. Didyminm cinereum Batsch, Fries, Syst. Afyc., III., p. 126. 



