68 THE MYXOMYCETES 



Sporangia scattered or gregarious, globose, even, or somewhat 

 wrinkled, dark red, reddish violet or purple, stipitate; stipe cylindric, 

 even, subconcolorous or blackish; columella small or none; capillitium 

 free from spores, whitish, with a slight pinkish tinge; spores dark brown 

 in mass, dark red when separated, globose, smooth, 7.5-8.5 /z. Plasmo- 

 dium dark red. 



The capillitium is very delicate, and when cleared of spores the 

 knot-like thickenings are seen to be very small and of a dark red color, 

 to which is probably due the pinkish tinge which marks the whole. A 

 part only of the thickenings are filled with lime granules. The dark red 

 granules of the sporangium walls are abundant and appear to form a 

 continuous crust. 



This is P. atrorubrum Peck, and his description has been closely 

 followed. The very brief description in Grevillea, however, antedates 

 the New York publication and, all inadequate as it is, no doubt applies 

 to the same thing. 



Not rare. Eastern and central United States and Canada, Washing- 

 ton; Rumania, Ceylon, Malay Peninsula. 



39. Physarum lilacinum Sturgis & Bilgram, non Fr. 1829 



Mycologia 9 : 324. 1917. 



Sporangia gregarious, stalked, globose, erect, pale lilac to pale 

 Indian-red in color, 0.5 mm. in diameter; sporangium wall mem- 

 branous, beset with rounded masses of lilac or reddish lime; stipe erect, 

 broad-based, tapering upwards, calcareous, furrowed, paler than the 

 sporangium or concolorous, 0.7-0.9 mm. long, about 0.1 mm. thick; 

 columella conical or columnar; capillitium delicate, rigid, persistent; 

 lime-knots small, rounded, composed of large, pale lilac or reddish, 

 spherical granules. Spores pale brown, almost smooth, 7-8 (x. 



Miss Lister records as var. cceruleum (Mycetozoa, 3rd ed., 30) a form 

 with pale blue sporangium, lime-knots and stalk, collected with the 

 typical form. 



Reported thus far only from Philadelphia. 



40. Physarum nucleatum Rex 



Proc. Ac. Nat. Sc. Phila. 1891:389. 

 PL V, Figs. 85, 86, 87. 



Sporangia gregarious, spherical, 0.5 mm. in diameter, white, stip- 

 itate; peridial wall membranaceous, rupturing irregularly, thickly 

 studded with rounded white lime granules; stipe about 1 mm., subu- 

 late, yellowish white, rugose; columella none; capillitium dense, snow- 



