44 THE NORTH AMERICAN SLIME-MOULDS 



first place, the sporangia are different in form and habit. They 

 are nearly always compound, convolute, or botryoid, in this 

 respect resembling T. polycepJiala. Besides, the sporangia are 

 uniformly much smaller, and show uniformly the strongly cal- 

 cified centre, much transcending anything seen in P. ncfroidcuui. 

 The stipe also is peculiar, an upward extension or sweep of the 

 common hypothallus which is usually very distinct or promi- 

 nent ; and, while the stipe is longitudinally wrinkled, it is much 

 less so than in the related species, and in a different way. The 

 spores are about the same in size, but differ in color, in this 

 respect agreeing rather with P. leucophcewn. 



Ometepe, Nicaragua. Collected by Mr. B. Shimek, 1892. 



21. PHYSARUM LEUCOPH^EUM Fries. 



1818. Physarum leucophceum Fries, Symb. Cast., p. 24. 



Sporangia scattered or gregarious, stipitate ; the peridium 

 globose or sub-depressed, plane, convex, but never umbilicate 

 below, erect, bluish ashen ; the stipe short, rugose, sub-sulcate, 

 white, attenuate upward from a thickened base or sometimes 

 from an indistinct hypothallus ; capillitium dense, the angles 

 flat-expanded, but with comparatively little lime, the internodes 

 often long, always thin and delicate ; columella none ; spore-mass 

 black, spores violaceous, minutely roughened, about S-io /u. 



This extremely delicate and beautiful form is certainly not 

 to be referred to No. 19. Fries, who seems to have known 

 of P. compression Alb. and Schw., and refers it to T. me tans 

 Rost. (see Syst. Myc., p. 130), annotates, as follows, the present 

 species : " Species especially remarkable in the stipe, in the 

 internal structure, and in its whole habit, nor is there any other 

 species with which it may be compared. . . . Peridium thin, 

 not uniform, presently breaking up into laciniate scales ; at 

 first yellow, then bluish ashen ; when empty, white. The form 

 inconstant, globose, depressed, but never umbilicate at base." 

 If we may judge by what Fries says on the subject, he certainly 

 distinguished clearly between this species and 7! nutans, to 



