PHYSARUM 81 



57. Physarum tropicale Macbr. 



N. A. Slime-Moulds 45. 1899. 

 1925. Physarum connatum (Pk.) Lister, Mycetozoa 3 ed. 51, in part. 



Sporangia scattered, gregarious, turbinate, short-stipitate, blue-gray, 

 about 1 mm. in diameter; peridium above iridescent, green, blue, etc., 

 dotted with minute flecks of white, below limeless, purple or bronze, 

 shading to the brown of the stipe; stipe short, stout, slightly rugose, 

 cylindric, non-calcareous, brown; columella none; hypothallus none; 

 capillitium abundant, the nodes generally calcareous, small, uniform, 

 angular, white, uniformly distributed; spore-mass black; spores dark 

 violet-brown, distinctly and closely warted, 12-15 fj,. 



A large handsome species recognizable by the peculiar turbinate 

 sporangium, with its iridescent peridial wall in which green strongly 

 predominates above, bronze below. The distinction between the 

 upper and lower peridium would suggest Craterium, but the internal 

 structure is not at all Craterium-like. The capillitium is typical of 

 Physarum. The color suggests those forms of P. leucopkceum Fr. 

 described by Rostafinski as var. violascens. From this species it is at 

 once distinguished by its much larger sporangia and larger and rougher 

 spores. 



Mexico. 



58. Physarum simplex M. E. Peck 



Am. Jour. Bot. 19 : 136. 1932. 



Sporangia stipitate, globose or a little depressed, minute, 0.2 to 

 0.3 mm. in diameter, very dark or sometimes dull yellowish; stipe 

 0.5 to 2 mm. long, slender, narrowed upward, irregularly grooved, 

 often very crooked and drooping above, light yellowish, little or not 

 at all calcareous; hypothallus none; peridium thin, often strewn with 

 abundant flakes of lime but sometimes nearly limeless, then appear- 

 ing black, persistent below; columella none; capillitium of very delicate 

 threads springing from the peridial floor, with a few small yellowish 

 gray calcareous nodes or none, and almost without dilations at the 

 intersections; spores violaceous brown, minutely roughened, 7-9 n in 

 diameter. 



A very delicate, minute species found twice in the vicinity of Salem, 

 Oregon. It is related to P. flavicomum Berk., differing in the longer 

 stipe, the more calcareous peridium and the less dense capillitium 

 with very few calcareous nodes. 



Oregon. Dead bark of Pseudotsuga. 



