60 Mycetozoa of North America 



resembles that of P. didermoides. This Hme if wetted and dried 

 again will form into vitreous plates or nodules, giving an appear- 

 ance like that in Lepidoderma. This feature is also found in 

 other species, as well as occasionally in the lime of the capillitium. 

 The numerous lime-knots, usually small and rounded and with 

 short connecting threads, form a somewhat persistent capillitium. 

 The foregoing distinguishing characters apply more to the 

 sessile, subglobose sporangia and plasmodiocarps, rarely com- 

 pressed, and usually developing on wood. The laterally com- 

 pressed, stalked sporangia with firmer walls are usually on dead 

 herbage or composts, and are easily recognized. From P. cine- 

 reum the sessile sporangia and plasmodiocarps are separated by 

 the darker and larger spores. The spores of P. compressum re- 

 semble those of P. vernum Somm. with which the plasmodiocarps 

 have been confused, but P. vernum is not known definitely from 

 North America, and reports of its collection are doubtful. P. 

 vernum forms large, massive sporangia and plasmodiocarps with 

 thick, densely calcareous walls, the lime more everrfy distributed. 

 Besides, it develops on herbage, whereas similar appearing forms 

 of P. compressum are found on wood. P. lepidoideum is probably 

 a form of the present species with naturally rewetted lime. Such 

 forms are found occasionally. The specimens referred to P. 

 vernum (Mycologia 30: 351. 1938) are also phases of P. com- 

 pressum, having scaly walls but small spores. P. compressum 

 forms small developments in contrast with the large fruitings of 

 P. notabile in the later months. 



37. Physarum notabile Macbr. N. A. Slime-Moulds ed. 2. 80. 

 1922. 



Didymium connatiim Peck, Rept. N. Y. State Mus. 26: 74, 1874. (N. Y. 



B. G. nos. 7979, 7980, authentic material.) 

 Physarum troplcale{?) Macbr. N. A. Slime-Moulds 45. 1899. 

 Physarum connatiim (Peck) Lister, Mycetozoa ed. 2. 71. 1911. Not P. con- 



natum Ditm. 1817, nor P. connatum Schum. 1803. 



Plasmodium white or gray (Lister). Sporangia scattered, 

 free or connate, subglobose, turbinate or reniform, occasionally 

 flattened above or beneath, 0.5 to 0.7 mm. diam., grayish white, 

 stalked, or, forming subglobose, sessile sporangia, or plasmodio- 

 carps, which may be clustered or angled by mutual pressure; 

 sporangial wall membranous, with clustered deposits of lime- 

 granules on the outside. Stalk stout, furrowed, dark brown, red- 



