236 THE MYXOMYCETES 



KEY TO THE GENERA OF THE RETICULARIACE^ 



a. Surface alveolar, the alveoli representing the caps of the 

 sporangial units; from each cap four to six threads descend 



almost to the base 3. Dictydicethalium 



a. Surface not alveolar b 



b. Pseudocapillitium of broad, perforated plates 1. Enteridium 



b. Pseudocapillitium of flat, irregular plates fraying out 



into threads 2. Reticularia 



1. Enteridium Ehrenberg 

 Spreng. Jahrb. 1 : 55. 1818. 



Fructification an aethalium, the spore-mass permeated by plates with 

 large openings, resulting in a pseudocapillitium forming an intricate net- 

 work. Distinguished from Reticularia by the broad, perforated plates 

 of the pseudocapillitium which do not fray out into marginal threads. 



The fructification is presumably homologous with that of Reticularia 

 and the reasons for regarding it as a true aethalium are discussed in 

 connection with the treatment of that genus. 



KEY TO THE SPECIES OP ENTERIDIUM 



o. Spores free b 



a. Spores clustered, rarely free c 



b. iEthalium pulvinate, reddish brown; spores brown in mass, 



reticulate 1- E- rozeanum 



b. yEthalium thin, broadly effused, dark olivaceous brown; 



spores brownish olive in mass, warted 5. E. yabeanum 



c. JLthalium plasmodiocarpous 2. E. liceoides 



c. ^Ethalium pulvinate • • • • ^ 



d. ^Ethalium olivaceous, of moderate size 3. E. olivaceum 



d. yEthalium very small, usually under 2 mm. in diameter; 



pale umber 4. E. minutum 



1. Entertdium rozeanum Wingate 



Proc. Ac. Nat. Sc. Phila. 1889 : 156 

 PI. XV, Figs. 386, 387, 388. 



1893. Reticularia splendens Morg., Jour. Cin. Soc. Nat. Hist. 15 : 137. 

 1899. Enteridium splendens (Morg.) Macbr., N: A. Slime-Moulds 151. 



^Ethalium pulvinate, even or somewhat irregularly swollen or 

 inflated, lobate or compound, covered by a thin, smooth, shining, 

 brown cortex, 0.5-6 cm. in diameter; hypothallus white, often extend- 

 ing widely around the base; true capillitium none, the pseudocapilli- 

 tium of thin, yellow-brown membranes forming the perforated sponge- 

 like framework characteristic of the genus; spore-mass umber; spores 

 by transmitted light pale yellow, about two-thirds of the surface 

 reticulate, the remainder finely verrucose, 7-9 ix. 



