D I DERM A 141 



14. DiDERMA ROANENSE (Rex) Macbr. 



1893. Chondrioderma roanense Rex, Proc. Phil. Acad., p. 368. 

 Sporangia scattered, discoidal, thin, flattened or slightly convex 



above, plane or plano-concave below, umber-brown, stipitate, the out- 

 er peridium smooth, brittle, rupturing irregularly, the basal frag- 

 ments somewhat persistent, concrete with the inner peridium, which 

 is pure white, except near the columella, and punctate ; stipe short, 

 variable, longitudinally ridged, jet-black; hypothallus none; columella 

 flat, discoidal, pale ochraceous; capillitium sparse, white or colorless, 

 composed of simple, rarely forked, sinuous threads occasionally joined 

 by lateral branches; spores dark violaceous, distinctly warted, 12-14 fi. 



This species is readily distinguished by its color. The sporangia, 

 found on rotten wood, are large, 1 mm., brown, and have thick, per- 

 sistent walls. Dr. Rex considered that the species differs from other 

 related forms not only in color, but in the well-marked discoidal 

 columella and the jet-black irregular stipe. It is perhaps most nearly 

 related to the following species. 



Tennessee. 



15. DiDERMA RADIATUM (Linn.) Morg. 



Plate XVIII., Fig. 8 



1753. Lycoperdon radiatum Linn. (?) Sp. PL, 1654. 



1797. Didymium stellare Schrad., Nov. Gen. PL, p. 21. 



1801. Diderma stellare (Schrad.) Persoon, Syn., p. 164. 



1875. Chondrioderma radiatum (Linn.) Rost., Mon., p. 182. 



1894. Diderma radiatum (Linn.) Morg., Jour. Cin. Sac, p. 66. 

 1899. Diderma stellare Schrad., Macbr., N. A. S., p 104 



1911. Diderma radiatum List, Mycetozoa, 2nd ed., p. 112. 



Sporangia scattered, depressed-globose, sometimes also flattened be- 

 low, stipitate, smooth or slightly corrugate, ashen or brownish, about 

 1 mm. in diameter, the peridium dehiscing irregularly or somewhat 

 radiately from above downwards, the segments reflexed, the inner 

 layer not distinguishable, or inseparable; stipe short, stout, brownish, 

 sometimes almost lacking; hypothallus not conspicuous, but some- 

 times sufficient to connect the bases of adjacent stipes; columella 

 large, hemispherical or globose, pallid or yellowish ; capillitium abun- 

 dant, of slender generally simple, colored threads, paler at the furcate 

 tips; spores dark violaceous, minutely roughened, 8-11 /t. 



