PHYSARUM 39 



slender ; hypothallus scant, black, or none ; columella none ; 

 threads of the capillitium yellow, delicate, connecting the rather 

 dense and abundant lime granules ; spore-mass brownish black, 

 spores violaceous, minutely but distinctly spinulose, 9-1 1 /u,. 



This species is easily recognizable by its brilliant yellow color, 

 somewhat rugose, sometimes scaly, peridium, its richly calca- 

 reous capillitium, also bright yellow where not weathered or 

 faded, its dark brown, translucent, non-calcareous stem. 



It occurs in Iowa on the bark of fallen Popiilus. 



We have followed here the synonymy of Lister, who has 

 compared American specimens with the type of Cooke's species. 

 We except Ohio specimens, called by Morgan Craterium maydis, 

 characterized by longer stems and less calcareous peridium, 

 the lime in the form of scattered scales. This species will be 

 found listed in its appropriate place. 



Massachusetts, New York, Ohio, Carolinas, Iowa. 



17. PHYSARUM VARIABILE Rex. 



1893. Physaruin variabile Rex., /V<?<r. Phil. Acad., p. 371. 



Sporangia scattered, stipitate, sub-stipitate or sessile about 

 i mm. high ; regularly or irregularly globose, ellipsoidal, 

 obovate or cylindric-clavate in shape ; sporangium wall some- 

 times apparently thick, of a dingy yellow or brownish ochre 

 color, slightly regulose on the surface, crustaceous, brittle, rup- 

 turing irregularly, sometimes thin, translucent, covered externally 

 with flat circular lime-masses falling away in patches ; stipes 

 nearly equal, occasionally much expanded at the base, rough 

 longitudinally rugose, variable in size, sometimes one-third of a 

 milimetre high, sometimes a mere plasmodic thickening of the 

 base of the sporangium ; color of stipes varying from a yellowish 

 white to a dull brownish gray ; capillitium a small-meshed net- 

 work of delicate colorless tubules with large, many-angled, 

 rounded masses of white, or rarely yellowish white lime grafi- 

 ules at the nodes ; no true columella, but often a central irreg- 

 ular mass of white lime granules ; spores dark violet brown, 

 verruculose, 9-10 ft. 



