42 THE MYXOMYCETES 



g. Dull'gray, somewhat iridescent; limeless 16. P. nudum 



h. Red 16a. P. nasuense 



h. White or pallid * 



h. Yellow or ochraceous j 



h. Some shade of brown k 



i. Laterally compressed, chalk white; spores sub reticulate. . 17. P. echinosporum 



i. Laterally compressed, white or gray, sometimes yellow- 

 ish; inner peridium colorless or pallid 18. P. bivalve 



i. Somewhat compressed or terete, white or pallid; inner 



peridium purplish 19. P. bitectum 



i. Hemispherical, rarely laterally compressed, snow-white; 



outer peridium diderma-like, remote 20. P. diderma 



j. Pale yellow to yellowish white; plasmodiocarpous ; 



spores 9-14 n 21. P. alpinum 



j. Ochraceous, sporangiate; peri dial walls distant; 



spores 8-10 /x 22. P. conglomeratum 



j. Deep ochraceous to pallid; short-plasmodiocarpous 



to reniform, densely crowded; spores spinulose, 11-13 \x 23. P. contextum 

 j. Ochraceous to pallid ; usually sporangiate, not crowded ; 

 outer peridium breaking up into scales, inner peridium 

 persistent below; spores warted, 11-13 n 24. P. mortoni 



k. Sporangiate; sessile or short-stalked, rarely plasmodio- 

 carpous; lower part remaining as a cup 25. P. brunneolum 



k. Usually plasmodiocarpous; pinkish brown or bronze. ... 26. P. aneum 



k. Usually plasmodiocarpous; outer peridium yellow-brown, 

 dehiscing by triangular lobes revealing the pure white 



inner surface 27. P. bogoriense 



I. Columella large, conspicuous tn 



I. Columella small, conical, sometimes imperceptible n 



I. Columella lacking, pseudocolumella sometimes present q 



m. Columella long, slender, acuminate; sporangia ellip- 

 soidal, greenish 28. P. penetrate 



m. Columella cylindrical; sporangia pink 29. P. puniceum 



m. Columella stout, cylindrical or clavate, sometimes re- 

 duced; sporangia globose, grayish white or pale brown. . 30. P. crateriforme 



m. Columella subglobose or clavate, yellow 31. P. listen 



m. Columella white, conical, attaining one-third the height 



of the sporangium; stipe stout, yellowish 32. P. perjectum 



n. Sporangia pale bluish gray to white; nodes white or 



yellowish 33. P. globuliferum 



n. Sporangia ashy brown; nodes orange to brownish. ... 34. P. murinum 



n. Sporangia yellow or orange ° 



n. Sporangia lilac to purple or blue P 



o. Honey yellow; columella and stipe white, yellow or 



tawny; nodes white 35. P. melleum 



o. B right yellow; columella and stipe yellow; nodes yello w. . 36. P.citrinum 



o. Yellow-orange to bronze tawny; stipe orange-red, darker 



at base 37. P. pulcherripes 



p. Sporangia and stalk deep purple-red; nodes small,purple 38. P. pulcherrimum 

 p. Pale lilac to pale red, rarely blue 39. P. lilacinum 



