PHYSARUM 35 



1831. Physarumcinereum Schweinitz, N. A. F., No. 2291. 

 1875. Physarum cinereum Batsch, Rost., Mon., p. 102, Fig. 71. 



Plasmodium watery white, or transparent, wide streaming on 

 decaying sod, etc. Sporangia sessile, closely gregarious or even 

 heaped, sub-globose, elongate or plasmodiocarpous, more or 

 less calcareous, gray ; peridium simple, thin, more or less densely 

 coated with lime ; capillitium strongly developed, the nodes more 

 or less richly calcareous, the lime knots rounded, angular ; spore- 

 mass brown, spores violaceous brown, 10-12 //., distinctly warted. 



This delicate, inconspicuous species is well defined by the 

 characters given. It occurs not rarely on richly manured 

 ground, in meadows, lawns, or even on the open prairie. The 

 plasmodium may form rings several inches in diameter, scat- 

 tered here and there over a surface several square feet in 

 extent, in fruit ascending the blades of grass, completely cov- 

 ering these with the crowded sporangia. The color of the fruit 

 is well described in the specific name, cinerenm, ashen gray. 

 The spores are very delicately papillate, in some specimens, 

 however, almost smooth. 



Common. New England west to the Black Hills and Pacific 

 coast. 



ii. PHYSARUM PLUMBEUM Fries. 



1829. Physarnm pliimbeum Fries, Syst. Myc., III., p. 142. 



Sporangia gregarious, occasionally clustered, globose, or de- 

 pressed globose, sessile ; dull plumbeous or grayish brown ; the 

 peridium thin, with few minute calcareous scales or none ; 

 columella none ; capillitium lax, the nodules rather large, 

 white, irregularly branched ; spore-mass black, spores smooth, 

 violaceous, 7-8 /i. 



This species has been rehabilitated by Mr. A. P. Morgan, 

 following the slender references of Fries, I.e. The species is 

 supposed by the authors named to be that figured by Micheli, 

 PL 96, Fig. 9. In outward form this species is not unlike No. 

 13, below ; but the spores of the two species are very different. 



Apparently not common. Our only specimens are from Ohio. 



