144 THE NORTH AMERICAN SLIME-MOULDS 



branched threads; spores dark violaceous-brown, studded with scat- 

 tered warts, 10-11 )u. 



Not uncommon, especially on rotten oak logs. Easily recognized 

 by the peculiar form of the fruit, spherical before dehiscence, flori- 

 form after. Unlike most species, this form often fruits in dark 

 places, in the interior of a log, even in the ground. 



New England, Ontario to Iowa and Nebraska, and south. 



19. DiDERMA RUGOSUM (Rex) Macbr. 

 Plate XVIII., Fig. 10. 



1893. Chondrioderma rugosum Rex, Proc. Phil. Acad., p. 369. 



Sporangia gregarious, scattered, white or ashen, rugulose over the 

 whole surface, the ridges marking the lines of subsequent rupture or 

 dehiscence, the peridium thin papyraceous, stipitate; stipe well devel- 

 oped about equal to the sporangium, subulate, almost black; hypo- 

 thallus none; columella distinct, generally white, sometimes small, 

 globose, sometimes penetrating the sporangium, to one-half the 

 height ; capillitium white or colorless, the filaments freely forked and 

 combined by lateral branches into a loose network attached to the 

 columella and basal wall below and the upper sporangial wall above ; 

 spores violaceous-brown, warted, 8-10 /x. 



This species is well designated rugosum, and is recognizable at 

 sight by its wrinkled, areolate surface. Related to D. radiatum in 

 the prefigured dehiscence, but otherwise very distinct. Liable to be 

 overlooked as a prematurely dried physarum. Rare. Plasmodium 

 gray. 



North Carolina, Iowa. 



4. Lepidoderma DeBary 



1858. Lepidoderma DeBy., MS. Rost., Versuch, p. 13. 



Sporangia stalked or sessile; peridium cartilaginous, adorned with- 

 out with large calcareous scales, superficial or shut in lenticular cavi- 

 ties; capillitium non-calcareous.^ 



^ If a sporangium of L. tigrinum be mounted in water and treated to weak 

 solution of hydro-chloric acid we may easily discover that the crystals, which 

 so wonderfully adorn the outer wall in this and other species, consist, in part 



