DiDERMA 91 



Capillitium consisting of a network of rigid, hyaline threads, with 

 branching and anastomosing, yellowish or brownish lime-knots. 



A SINGLE SPECIES. 



1. Leocarpus fragilis (Dicks.) Rost. Mon. 132. 1874. 

 Ly coper don fragile Dicks. PI. Crypt. Brit. 1: 25. 1785. 



Plasmodium lemon, then orange-yellow (Lister). Sporangia 

 clustered, obovoid, rarely globose, 2 to 4 mm. long, stalked or 

 occasionally sessile, smooth, yellowish brown, chestnut or pur- 

 plish brown, shining, sometimes dehiscing in revolute lobes; outer 

 layer of the sporangial wall cartilaginous, brittle, orange-brown, 

 usually with dense deposits of lime-granules on the inner side; 

 inner layer a firm, hyaline membrane, giving attachment to the 

 capillitium. Stalk short, or as long as the sporangium, weak, 

 yellowish, translucent, rising from a membranous hypothallus. 

 Capillitium a network of rigid, hyaline threads with flattened ex- 

 pansions at the axils, connected with angular, branching, and 

 anastomosing, yellowish or brownish lime-knots. Spores more 

 or less spinulose, very variable in size but usually 10-14 n diam., 

 sometimes slightly clustered, dark purplish brown or paler, with 

 a pale area of dehiscence. (Plate 15, fig. 4.) 



Type locality: England. 



Habitat: On dead leaves, twigs, and ground wood. 



Distribution: Common and abundant throughout the United 

 States and Canada. 



Illustration: Lister, Mycetozoa ed. 3. pi. 82. 



This strikingly handsome species is remarkable for the in- 

 constancy of the spores. They may be dark or paler, sometimes 

 strongly spinulose, and the size is often outside of the range given. 

 The capillitium may be almost entirely calcareous throughout, or 

 the solidly calcareous portion may be massed in a part or parts of 

 the sporangium, but connected with the hyaline net, the remain- 

 ing portion then being limeless or nearly so. 



Genus 9. DIDERMA Persoon, Neues Mag. Bot. 1 : 89. 1 794. 



Sporangia stalked, sessile, or forming plasmodiocarps; spo- 

 rangial wall of two layers (single in D. simplex and D. rugosum), 

 containing deposits of lime in granules (in crystalline nodules in 

 D. Trevelyani). Columella usually present. Threads of the 

 capillitium simple or branched, without lime-knots. 



Type species: Sphaerocarpus floriformis Bull. 



