294 A Monograph of the Muxogastres. 



A very distinct species, sporangia 1*5 2 mm. high, scattered 

 singly or in groups of two or three. Most nearly related to 

 Physarum nlliginosum, Fr., but readily distinguished by the 

 smaller spores, and the scattered stipitate sporangia. Readily 

 distinguished from the red form of Physarum Schumachcri, by 

 the absence of a columella and the pyriform sporangium passing 

 insensibly into the short stem. 



Physarum atrorubrum, Peck. ?.?vAcVeT,v*uv*t 



Scattered or gregarious, stipitate ; sporangia globose, even or 

 somewhat wrinkled, dark-red; stem cylindrical, even, blackish 

 or subconcolorous, capillitiurn when cleared of the spores 

 whitish, sometimes with a slight pinkish tinge ; columella none ; 

 spores globose, smooth, dark-brown in the mass, dark-red when 

 separated, '0003 '00035' in diameter ( = about 8 9 p.). 



Physarum atrorubrum, Peck, 31st Report, N. York State 

 Mus., p. 40; Sacc., SylL, vii., 1, n. 1202 (as Physarum atro- 

 piirpureum by mistake). 



Decaying wood. Adirondack Mt?., U. States. 



The plants are scarcely one line high. The capillitiurn is 

 very delicate, and when cleared of the spores the knot-like 

 thickenings are seen to be very small and of a dark-red colour, 

 to which probably is due the pinkish tinge sometimes observed. 

 The dark -red granules of the sporangium walls are abundant, 

 and appear to form a continuous crust. (Peck.) 



Physarum roseum, B. and Br. 



Sporangia stipitate, globose, broadly elliptical or obovate, 

 dark reddish-purple, sporangial wall covered with a thin crust 

 of minute granules of lime; stem brownish-purple, equal, 

 longitudinally wrinkled, filled with granules of lime, equal to 

 or usually longer than sporangium, expanding at the base into 

 a small, circular, pale brown, wrinkled hypothallus ; capil- 

 litiurn well developed, threads thin, tinged pink, with scattered, 

 elliptical, interstitial swellings containing lime, nodes not usually 

 enlarged or containing granules ; spores globose, smooth, 10 11 M 

 diameter. 



