DIDYMIACE^E 103 



present filiform, white or yellow, weak and short; spores dark, paler 

 at one side, coarsely warted, 12-14 ,u. Plasmodium orange-yellow. 



Recognizable at sight by the form and color of the sporangia. In 

 shape and posture these resemble the eggs of certain insects, and, 

 occurring upon dead leaves, generally where these have drifted against 

 a rotten log, they might perchance be mistaken for such structures. 

 With no other slime molds are they likely to be confused. The outer 

 peridium opens irregularly, or more rarely stellately. At the center 

 of the capillitium there is sometimes a calcareous core. 



A plasmodiform gathering of this species from California, which 

 might be mistaken for an entirely different thing, is yellow, sessile and 

 has adherent spores; looks like a badhamia; but is, after all, a leocarpus 

 and probably belongs here. The spores are irregularly clustered and the 

 badhamioid section of the capillitium seems to be dominant. 



Throughout the world; common. 



Family DIDYMIACE.E 



Capillitium non-calcareous, simple or somewhat branched, but not 

 forming an intricate net; peridium or stipe, or both, more or less cal- 

 careous; lime on surface of peridium often in the form of stellate crys- 

 tals or crystalline disks, sometimes scanty, rarely lacking; spores 

 violaceous black in mass. 



KEY TO THE GENERA OF THE DIDYMIACEjE 



a. Calcareous deposits in the form of stellate crystals b 



a. Calcareous deposits not stellate crystals c 



b. iEthalioid 1. Mucilago 



b. Plasmodiocarpous or sporangiate 2. Didymium 



c. Peridium strongly and continuously calcareous d 



c. Calcareous deposits not continuous; scattered; sometimes re- 

 stricted to basal portion; rarely lacking / 



d. Lime on surface of peridium in form of cylindrical peg-like 



protuberances 3. Physarina 



d. Lime forming a granular or firm shell e 



e. Peridium double; layers often distant 4. Diderma 



e. Peridium single 5. Wilczekia 



f. Calcareous deposits in the form of scattered, flattened scales 6. Lepidoderma 

 f. Calcareous deposits restricted to basal region, embedded in 



a dark, granular deposit 7. Leptoderma 



1. Mucilago Micheli ex A dans. 

 Fam. des PI. 2 : 7. 1763. 

 1791. Spumaria Pers., in Gmel., Syst. Nat. 2 : 1466. 



Fructification aethalioid, consisting of a large pulvinate mass com- 

 posed of numerous branched and anastomosing tubes as in Fuligo, the 



