48 THE MYXOMYCETES 



plish brown with a lighter area of dehiscence, minutely verruculose, 



11.5-14.8 m- 



This species is recognizable at once by its regular, uniform, de- 

 pressed, annulate or pitted sporangia, scattered evenly over the habitat 

 of rotten leaves or wood. In its form and habit it suggests a didymium. 



Colorado. 



6. Physarum sessile Brandza 



Ann. Sc. Univ. Jassy 11 : 116. 1921. 

 1898. Physarum variabile Rex var. sessile List., Jour. Bot. 36 : 114, in part. 



Sporangia solitary or gregarious, sessile, globose, 0.4-1 mm. in 

 diameter or forming elongated, sinuous plasmodio carps 2-10 mm. in 

 length and 0.5-0.8 mm. broad, grayish, bluish gray or pale gray; 

 peridium smooth, forming a fragile crust, formed by the aggregation 

 of transparent, calcareous granules 1 //. in diameter; pseudocolumella 

 globose, white; capillitium abundant, long-persistent, with rounded, 

 subequal, calcareous nodes 15-25 \x in diameter, formed of masses of 

 granules identical with those of the peridium, and which, like them, 

 become dissociated in water; connecting threads scanty, hyaline; 

 spores smooth, pale violaceous brown, 6-8 //. Plasmodium grayish 

 white. 



As originally described this included both this species and P. aureum. 

 In a later paper (1929), the author clearly distinguishes between the 

 two species and the later description is here followed. 



On dead leaves: West Indies; Rumania, Japan. The Lister mono- 

 graph records the species from Canada, Venezuela, Switzerland and 

 Ceylon. It is not certain whether the collections cited are this species 

 or P. aureum. 



7. Physarum serpula Morgan 



Jour. Cin. Soc. Nat. Hist. 19 : 29. 1896. 

 PI. Ill, Figs. 47, 48. 



1892. Physarum gyrosum Rost. ex Massee, Mon. 307, in part. 



1894. Badhamia decipiens (Curt.) Berk, ex Lister, Mycetozoa 32, in part. 



Sporangia sessile, sometimes subglobose, usually forming plasmo- 

 diocarps in the form of lines, rings or a simple network, 0.3 mm. in 

 diameter; yellow or ochraceous, fading; peridium thin, fragile, simple, 

 membranaceous but persistent, borne on a rather widely effused 

 hypothallus; capillitium of numerous yellow lime-knots connected 

 by short and scanty hyaline threads; spores globose, violaceous by 

 transmitted light, minutely warted, 10-13 /x. Plasmodium at maturity 

 greenish yellow. 



