MORPHOLOGY AND TAXONOMY OF THE SARCODINA 463 



Order III. Euplasmodida Lister. 



Spores exposed on surface of sporophores 



Sub-order 1. Exosporea 

 Spores in sporangia Sub-order 2. Myxogastres 



Sub-order 1. Exosporea Rostaf. 



One genus; spores exposed; no sporangia 



Genus Ceratiomyxa 



Sub-order 2. Myxogastres Fries. 

 (Key to genera adapted from MacBride, 1022.) 

 Spore mass black or violaceous, rarely ferru- 

 ginous Series A 



Spore mass never black; usually brown, yel- 

 low, etc Series B 



Scries A 



With delicate thread-like capillitium; 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. Cribrariales 



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. Physaridae 



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

 litium simple Family 2. Didymiidae 



Family 1. Physaridae MacBr. em. 



1 . Fructification an aethalium Genus Fuligo 



Fructification an aggregate of sporangia . . 2 



2. Peridium calcareous 3 



Peridium apparently limeless, at least out- 

 side 6 



3. Capillitium calcareous throughout . .Genus Badhamia 

 Capillitium largely hyaline 4 



4. Sporangia globose; dehiscence irregular 



( ienus Physarum 

 Sporangia vasiform or tubular 5 



5. Dehiscence by lid-covered opening (ienus 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 aethalium Genus Mucilago 



Fructification not an aethalium 2 



2. Peridium single 3 



Peridium double; outer one gelatinous. ... 4 



