Physarum 55 



brown, closely and minutely spinulose, 10-13 n diam. (Plate 7, 

 FIG. 4.) 



var. lividum Lister, Jour. Bot. 36: 161. 1898. (N. Y. B. G. nos. 11089, 11090, 

 authentic material.) 



Differing from the type in the gray sporangia being always ses- 

 sile, and having the sporangial wall usually of a single layer only; 

 in the lime-knots being more angular; and in the rougher, purple- 

 black spores being paler and smoother on one side. 



Type locality: Europe. (Sweden?) 



Habitat: On dead wood, leaves, stems, and straw. 



Distribution: Common throughout North America. 



Illustrations: Lister, Mycetozoa ed. 3. pi. 45, 46. 



The large developments of white, crowded sporangia are often 

 found on locust bark. The species is very variable, and the var. 

 lividum can hardly be regarded as more than a combination of 

 variations present in certain collections made in England. We 

 have here sporangia with single or double walls, and either may 

 have rounded or angular lime-knots. Spores paler on one side 

 are unknown here, or at least I have never observed them. In 

 my experience I have never found these variations separated and 

 alone, but always as patches within a development of typical 

 sporangia. The inner purplish wall may be absent, the capil- 

 litium unattached to the sporangial wall, or the lime aggregated 

 into a dense mass in the center of the sporangium. Different 

 combinations of these aberrations may be expected in any fruiting. 



32. Physarum pezizoideum (Jungh.) Pav. & Lag. Bull. Soc. Myc. 

 Fr. 19:87. 1903. (N. Y. B. G. no. 11236, authentic material 

 Pav. & Lag.) 



Trichamphora pezizoidea Jungh. Fl. Crypt. Jav. 12. 1838. 



Plasmodium grayish white (Lister). Total height 1 to 2.5 

 mm. Sporangia gregarious, erect or somewhat inclined, discoid 

 or saucer-shaped, 0.8 to 1.3 mm. broad, 0.2 to 0.4 mm. thick, 

 stalked, grayish white; sporangial wall membranous, with thin 

 deposits of lime-granules evenly distributed, breaking up at 

 maturity into areolae which remain attached to the capillitium 

 after dispersal of the spores. Stalk subulate, longitudinally 

 striate, reddish brown, translucent. Capillitium very variable, 

 consisting either of branching, anastomosing, colorless threads, 



