DIDERMA 105 



Rare on rotten logs in the forests ; September. Easily recog- 

 nized by the short-stiped, ashen sporangia which before dehis- 

 cence indicate by delicate tracings the lines which subsequent 

 cleavage is to follow. In texture the peridium resembles that 

 of D. floriforme. 



Pennsylvania, Ohio, Iowa, Virginia. 



The Linnaean description on which is based the specific name 

 D. radiatnin is wholly inadequate. It appears also by the testi- 

 mony of Linne _/?/.$, that L. radiatum Linn is a lichen! and the 

 name is so applied by Persoon. 



1 6. DIDERMA RUGOSUM (Rex) Macbr. 



PLATE XVI., Fig. 5. 

 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 subse- 

 quent rupture or dehiscence, the peridium thin papyraceous, 

 stipitate ; stipe well developed about equal to the sporangium, 

 subulate almost black ; hypothallus none ; columella distinct, 

 generally white, sometimes small, globose, sometimes penetrat- 

 ing the sporangium as in the next species, 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 /u,. 



This species is well designated rugosum, and is recognizable 

 at sight by its wrinkled, areolate surface. Related to D. radia- 

 tum in the prefigured dehiscence, but otherwise very distinct. 

 Liable to be overlooked as a prematurely dried Physarum. 

 Rare. Plasmodium gray. 



North Carolina, Iowa. 



17. DIDERMA FLORIFORME (Bull.} Pers. 



PLATE VIII., Figs. I, i a, i b. 



1791. Sphcerocarpus floriformis Bulliard, Champ., p. 142, t. 371. 

 1794. Diderma floriforme (Bull.) Persoon, Rom. N. Mag. Bot., p. 89. 



