122 THE MYXOMYCETES 



g. Outer wall firm, porcelain-like, separate from the 



inner wall h 



h. Sporangia in a dense, crustose mass; walls remote; 



spores 1 1-14 \i 7. D. crustaceum 



h. Sporangia gregarious; walls remote; spores 7.5-10 ju 8. D. globosum 

 h. Sporangia crowded, large, substipitate, walls close; 



inner wall and columella brownish or flesh colored 9. D. lyallii 



i. Sporangia sessile j 



i. Sporangia stipitate k 



j. Outer peridium white or pallid; inner distinct, 



ochraceous; capillitium duplex 10. D. niveum 



j. Outer wall porcelain- like, pale rose; capillitium 



simple 11. D. testaceum 



k. Sporangia greatly flattened, discoid 12. D. hemisphcericum 



k. Sporangia hemispherical to subglobose 13. D. montanum 



II. Leangium 



a. Sessile, rarely short-stipitate b 



a. Usually with a distinct stipe / 



b. Inner peridium distinct c 



b. Peridial layers more or less united d 



c. Brownish or pinkish gray; spores 12-13 fx 14. D. sauteri 



c. Ochraceous or olivaceous; spores 9-11 /jl 15. D. ochraceum 



c. White above, deep red below; columella clavate, 



rough, deep red 16. D. car-rubrum 



d. Middle layer of peridium subcrystalline; columella 



usually lacking 17. D. trevelyani 



d. Middle layer of peridium not crystalline e 



e. Peridium chocolate, marked before dehiscence with 



lines converging at apex; columella white 18. D. aster oides 



e. Pinkish or red-brown; columella cream colored, rough 19. D. antarcticum 

 e. Dark gray to nearly black; columella lacking 20. D. imperiale 



j. Stipe short, less than height of sporangium g 



f. Stipe equal to or exceeding height of sporangium h 



g. Ashy to brownish drab 21. D. radiatum 



g. Umber to red-brown 22. D. roanense 



g. Orange-red or vermilion 23. D. lucidum 



h. Brownish gray, ochraceous brown or umber; wall 



smooth; dehiscence revolute 24. D. floriforme 



h. White or grayish; wall rugulose, areolate and 



areolately dehiscent 25. D. rugosum 



1. Diderma effusum (Schw.) Morgan 



Jour. Cin. Soc. Nat. Hist. 16 : 155. 1894. 

 PI. VIII, Figs. 178, 179, 180, 181. 



1832. Physarum effusum Schw., Trans. Am. Phil. Soc. II. 4 : 257. 

 1898. Physarum crustijorme Speg., An. Mus. Nac. Buenos Aires 6 : 200. 



Fructification composed of flattened white sporangia massed in 

 plasmodiocarpous fashion, applanate, reticulate, or often forming a 



