82 THE NORTH AMERICAN SLIME-MOULDS 



2. LEOCARPUS FULVUS Macbr. n. s. 



PLATE XVI., Figs. 4, 4 a. 



Sporangia gregarious, scattered, ovoid or globose, pale yel- 

 lowish or fulvous, opening irregularly above, stipitate ; the 

 peridium double, the outer layer more or less calcareous, the 

 inner delicate, almost indistinguishable, persistent below as a 

 shallow cup ; the stipe long, weak, striate, fulvous ; hypothallus 

 distinct, venulose, or more or less continuous ; capillitium pallid 

 or white, dense, with here and there rather large, yellow calca- 

 reous nodes ; columella none ; spore-mass black ; spores by 

 transmitted light, dark brown, rough, 13-15 /*. 



This interesting form is from Colorado, and suggested at first 

 a Diderma ; but the capillitium is entirely unlike that of a 

 Diderma in color and structure, and plainly belongs here. 

 Plasmodium yellow, on fallen leaves and twigs. Our material is 

 from Mr. E. Bethel, Denver. 



B. 



Key to the Genera of the Didymieze. 



A. Fructification cethalioid I. MUCILAGO 



B. Fructification in form of distinct sporangia. 



a. Calcareous deposits in form of stellate crystals, frosting the 



surface 2. DIDYMIUM 



b. Calcareous deposits forming a superficial crust 3. DIDERMA 



c. Calcareous deposits in the form of large superficial scales 



4. LEPIDODERMA 



1. Mucilago (Mich.} Adans. 



1729. Mucilago Micheli, Nov. PL Gen. (in part). 



1763. Mucilago (Mich.), Adanson, Fain, des PL, II., p. 7. 



1791. Spnmaria Pers. in Gmelin, Syst. Nat., II., p. 1466. 



Fructification aethalioid, consisting generally of large cushion- 

 shaped masses covered without by a white foam-like crust ; 

 within, composed of numerous tubular sporangia, developed 

 from a common hypothallus, irregularly branched, contorted 

 and more or less confluent ; the peridial wall thin, delicate, 



