D I DERM A 133 



hypothallus more or less plainly in evidence, white or pale alutaceous ; 

 columella distinct, though often small, globose, yellowish ; capillitium 

 variable in quantity, sometimes abundant, brown, somewhat branch- 

 ing and anastomosing outwardly, the tips paler; spores minutely 

 roughened, dark violaceous, about 10 /x. 



This species has the outward seeming of a didymium, but is plainly 

 different as that genus is here defined, since the calcareous crust, al- 

 though inclined to be pulverulent, is made up of minute granules, not 

 crystals, of lime. The hypothallus is sometimes hardly discoverable, 

 anon well developed, out-spread, rugulose, far beyond the limits of 

 the fructification. In his Monogj-nph, p. 175, Rostafinski includes 

 here Physarum stromateum Link. In the Appendix he is inclined to 

 raise Link's form to the dignity of a distinct species, basing the 

 diagnosis upon the superposition of the sporangia in certain cases, a 

 feature entirely unknown to Link's description and of extremely un- 

 certain value, since by their crowding the sporangia are liable always 

 to be pushed above each other. We therefore regard C. stro/nateum 

 (Link) Rost. as a synonym of the present species, as the description. 

 Link, Handb., III., 409, indicates, so far as it goes. 



3. DiDERMA SIMPLEX (Scliroet.) Lister. 



1885. Chondrioderma simplex Schroet., Krypt. Fl. Schles., III., 1, p. 123. 

 1911. Diderma simplex List., Mycetozoa, 2nd ed., p. 107. 



"Plasmodium bright yellowish brown." Sporangia gregarious, ses- 

 sile, globose or depressed globose, .3-.5 mm., or anon plasmodiocar- 

 pous, brown or brick-red when fresh, becoming paler, ochraceous, etc. ; 

 hypothallus everywhere in evidence ; columella ill-defined ; capillitium 

 scanty, the threads delicate, pale, branching as they join the peridial 

 wall; spores dull violaceous, slightly roughened, 8-10 /x. 



A rather crude, primitive representative of this beautiful genus. 

 The inner peridium seems to be lacking, — a comfort to Rostafinski ! 

 Rare. Our best specimens are from New Jersey, by courtesy of Dr. 

 C. L. Shear. These went to fruit on leaves and branches of Vac- 

 cinium. It seems to affect the heather of Europe, moorland, etc. I 

 have also specimens from the herbarium of the lamented Dr. Rex. 

 These are more plasmodiocarpous, but open beautifully by a median 



