116 THE NORTH AMERICAN SLIME-MOULDS 



ii. Peridium small, globose. 



* Stipe dark brown or black; columella dark, ob- 

 solete or none . . . 10. D. nigripes 

 ** Stipe generally paler, of various tints of brown, 

 orange, etc. 



t Columella pale or white, nearly smooth 

 11. D. xanthopus 

 tt Columella, yellow, discoid, rough 



12. D. eximium 

 iii. Peridium turbinate, columella hemispheric 



13. D. trochus 

 iv. Peridium annulate ... 14. 

 2. Calcareous crystals forming a distinct crust. 



A. Fructification wholly plasmodiocarpous 



B. Sporangia ill-defined, sessile, plasmodiocarpous. 



a. Spores generally nearly smooth 



b. Spores very rough, obscurely banded 



EXTRA-LIMITAL 



a. Sporangia discoid, spores reticulate 19. D. intermedium 



h. Stipe, columella, peridium, orange-brown 20. D. leoninum 



1. DiDYMIUM COMPLANATUM (Batsch) Rost. 



Plate XVI., Fig. 8. 



1786. Lycoperdon complanatum Batsch, Elench. Fung., I., p. 251. 



1829. Didymium serpula Fr., Syst. Myc., III., p. 126, Rost., A pp., p. 21. 



1875. Didymium complanatum (Batsch), Rost., Mon., p. 151. 



1899. Didymium complanatum (Batsch) R., Macbr., A'^. A. S., p. 85. 



1911. Didymium complanatum Rost, List., Mycetozoa, 2nd ed., p. 127. 



Fructification plasmodiocarpous, creeping, flattened, vein-like, an- 

 nulate or reticulate, the dark-colored peridium covered with white, 

 but not numerous crystals; hypothallus none; columella none; capil- 

 litium much branched, violaceous threads combined to form a rather* 

 dense net which bears numerous, peculiar, rounded vesicles, yellowish 

 in color, 30-50 fi in diameter; spores minutely warted, 7-9 jx, viola- 

 ceous-brown. 



The defining characteristics here are the curious supplementary 

 vesicles. These are evidently plasmodic, embraced, shot-through, by 

 all the neighboring capillitial threads, withal warted like a spore. 

 They remind of the curious, belated, spore-like but giant cells found 

 in stipes, as in arcyriaceous forms. With all the wealth of his prolix, 



