SPECIAL MORPHOLOGY AND TAXONOMY OF SARCODINA 351 



Sub-order 1. Exosporea, Rostaf. 



One genus; spores exposed; no sporangia 



Genus Ceratiomyxa 



Sub-order 2. Myxogastres, Fries. 



(Key to genera adapted from MacBride, 1922) 



Spore mass black or violaceous, rarely ferru- 

 ginous /Series A 



Spore mass never black; usually bro^vii, yel- 

 low, etc Series B 



Series A 



With delicate thread-like capiUitium; spor- 

 angia more or less calcareous Legion 1. Physarales 



With capillitium and columella; rarely cal- 

 careous Legion 2. Stemonitales 



Series B 



Capillitium imperfect or none; spores brown, 



rarely purple Legion 3. Cribariales 



Capillitium of interwoven plates or tubules; 



spores pale or ashen Legion 4. Lycogalales 



Capillitium of sculptured threads; spores yel- 

 low Legion 5. Trichiales 



Legion 1. Physarales MacBr. 



Fructification often calcareous throughout; 



capillitium intricate Family 1. Physarid.e 



Lime in peridium only, or also in stipe; capil- 

 litium simple Family 2. Didymiid^ 



Family 1. Physaridse, MacBr. em. 



1. Fructification an a^thalium Genus Fuligo 



Fructification an aggregate of sporangia ... 2 



2. Peridium calcareous 3 



Peridium apparently limeless, at least 

 outside 6 



3. Capillitium calcareous throughout . . Genus Badhamia 

 CapiUitium largel}^ hyaline 4 



4. Sporangia globose; dehiscence irregular 



Genus Physarum 

 Sporangia vasiform or tubular 5 



5. Dehiscence by lid-covered opening. .Genus Craterium 

 Dehiscence irregular; peridium inverted 



Genus Physarella 



6. Sporangia sessile with irregular outlines 



Genus Cienkowskia 



Sporangia distinct Genus Leocarpus 



Family 2. Didymiidae, MacBr. em. 



1. Fructification an sethalium Genus Mucilago 



Fructification not an setlialium 2 



2. Peridium single 3 



Peridium double ; outer one gelatinous .... 4 



3. Calcareous deposits crystalline; stellate 



Genus Didymiwn 

 Calcareous deposits in form of scattered 



scales Genus Lepidoderma 



4. Outermost peridium gelatinous Genus Collodenna 



Outer peridium hardened Genus Diderma 



