PHYSARUM 43 



q. Sporangia with a conspicuous, white calcareous nucleus 



at center r 



q. Sporangia non-nucleate s 



r. Globose, white; peridium membranous, capillitium 



dense 40. P. nucleatum 



r. Gray or brown; capillitium delicate 41. P. wingatense 



r. Ovoid or cylindric, crowded; outer peridium white, 

 calcareous, sometimes lacking; inner peridium lead 



colored; spores 12-15 fi 42. P. didermoides 



r. Lime mass often columella e; stalked, sessile or plas- 



modiocarpous; spores 7-10 ju 43. P. mutabile 



r. Sporangia multilobate, contorted 44. P. nicaraguense 



r. Discoidalor top-shaped, depressed or umbilicate above 45. P. discoidale 



s. Sporangia not globose or lenticular t 



s. Sporangia globose, subglobose or lenticular « 



t. Sporangia white; thin, saucer-shaped 46. P. javanicum 



t. Sporangia white or ashy; laterally compressed, circu- 

 lar to reniform, sometimes sessile and almost plas- 



modiocarpous 47. P. compressum 



t. Sporangia pale purple; obovate or wedge-shaped; 



stipe pallid, weak, often flattened 48. P. straminipes 



u. Brilliant purple; short-stemmed, sometimes sessile 49. P. newloni 



u. Rose-red; stipe exceeding sporangium 50. P. roseum 



u. Blue or bronze, iridescent, spotted with red or orange; 



stipe brilliant orange 51. P. psittacinum 



u. Gray, white or iridescent v 



u. Yellow or yellowish w 



v. Stipe snow-white, fragile; peridium didymium-like. . . 52. P. leucopus 

 v. Stipe pale fuscous to brown, stout, short, wrinkled; 



peridium white to bluish 53. P. leucophceum 



v. Stipe bright yellow; nodes small, yellow 54. P. maculatum 



v. Sporangia depressed-globose, stipitate or sessile, 

 strongly calcareous; stipe dark, opaque, sometimes 



frosted with white granules 55. P. notabile 



v. Stipe long, slender, bright brown; sporangia nearly 



globose, rather small, 0.4-0.6 mm 56. P. pusillum 



v. Stipe shorter, robust, dark; sporangia larger, irides- 

 cent, with scanty lime deposits 57. P. tropicale 



w. Color dull; pale, ochraceous, fulvous to nearly black x 



w. Bright yellow y 



x. Dull yellow to dusky; minute; spores 7-9 /x 58. P. simplex 



x. Yellowish white to fulvous; stipe weak, often lacking; 



spores dark, rough, 12-15 n 59. P. albescens 



x. Pale or deep ochraceous; spores violaceous, 10-12.5 y. 60. P. citrinellum 

 x. Dingy yellow to brownish ochraceous, often obovate 



or cylindrical; stipe short 61. P. variabile 



x. Peridium membranous, ochraceous above, lower part 



and stipe with flesh tints 62. P. carneum 



x. Yellowish to sooty, often iridescent 63. P. flavicotnum 



x. Sulphur-yellow to olive-yellow; nodes large, white. . . 64. P. sulphur eum 



