PHYSARUM 57 



1829. Diderma contcxium Persoon, Fries, Syst. Myc, III., p. 111. 



1873. Diderma ocliroleucum Berk. & C, Grev., II., p. 52. 



1879. Diderma fiavidum Pk., A^. Y. Rep. State Mus., XXXI., p. 55. 



Sporangia distinct, sessile, densely crowded, sub-rotund reniform 

 more often elongate, interwoven ; peridium double ; the outer rather 

 thick, calcareous, yellow, or yellowish white, the inner thin, yellow- 

 ish ; capillitium white, containing numerous large, irregular calcare- 

 ous granules; columella none; spores deep violet, 11-13 fx, covered 

 with minute spinules. 



This singular species occurs not rarely upon the bark of fallen 

 twigs, upon bits of straw or grass-stems lying undisturbed upon the 

 ground. In such a position the slime-mould covers, as with a sheath, 

 the entire substratum. The outer peridium, especially its upper 

 part, is entirely evanescent, our Fig. 3 shows the sporangia with 

 upper outer peridium wanting. Not rare in summer and autumn. 



New England, New York, Pennsylvania, Ohio, Wisconsin, Illi- 

 nois, Iowa, Colorado, Oregon, Nicaragua. 



10. Physarum conglomeratum (Fr.) Rost. 



1803. Spumaria granulata Schum., Enum, PL SaelL, II., p. 196, No. 1419. 



1803. Spumaria minuta Schum., /. c. 



1829. Diderma granulatum Schum., Fries, 5. M., III., p. 110. 



1829. Diderma minutum Schum., Fries, /. c, p. 111. 



1829. Diderma conglomeratum Fries, /. c, p. 111. 



1875. Physarum conglomeratum (Fr.) Rost., Mon., p. 108. 



1892. Physarum rostafinskii Massee, Mon., p. 301. 



1894. Physarum conglomeratum Rest, Lister, Mycetozoa, p. 58. 



1899. Physarum conglomeratum (Fr.) Rost., Macbr., N. A. S., p. 31. 



1911. Physarum conglomeratum Rost., List., Mycetozoa, 2nd ed., p. 80. 



Sporangia depressed, globose, or irregular, sessile, more or less 

 aggregated, ochraceous-yellow, peridium double, the outer, thick, 

 cartilaginous, at length irregularly ruptured, and reflexed, disclosing 

 the more delicate, ashen-gray, inner membrane which encloses capilli- 

 tium and spores ; capillitium abundant, showing large, white irregular 

 calcareous thickenings which are often consolidated in some spo- 

 rangia tend to aggregate at the centre ; spore-mass brown, spores vio- 

 laceous, slightly roughened, 8-10 /x. 



This beautiful species shows a peridium as distinctly double as in 



