124 THE MYXOMYCETES 



0.7-1 mm. broad; outer layer smooth, shell-like, inner membranous, 

 gray or somewhat iridescent; columella convex, rough, ochraceous to 

 flesh colored; capillitium rather stout, of straight to flexuose, branch- 

 ing threads, pale to purplish, with numerous dark, fusiform thicken- 

 ings; spores dark purple, rather roughly warted, 11.5-12.3 ju. 



Miss Lister says the inner wall is flesh colored. This is not the case 

 in our specimens, received from M. Meylan. The spores also average 

 12.3 ix, somewhat larger than as described. 



Switzerland, abundant in the mountains, Hungary. 



3. DlDERMA CHONDRIODERMA {de B. & Rost.) G. List. 



Mycetozoa ed. 3. 258. 1925. 

 PI. XXI, Figs. 566, 567, 568, 569. 



1872. Didymium chondrioderma de B. & Rost., in Alex. Stroj. 89. 



1875. Chondrioderma alexandrowiczii Rost., Mon. 169. 



1913. Diderma arboreum G. List. & Petch, Jour. Bot. 51 : 2. 1913. 



Sporangia scattered, discoid, sessile or rarely stalked, 0.5-0.7 mm. 

 in diameter, or forming expanded and lobed, flattened plasmodiocarps 

 1-3 mm. in diameter, white or purplish gray from lack of lime; spo- 

 rangium wall membranous with deposits of round or angular lime 

 granules either united to form a thin crust or sparsely distributed, 

 often with scattered deposits of refuse matter; stalk, when present, very 

 short, dark brown; columella flesh colored, sometimes nearly obsolete; 

 capillitium rather coarse, purplish or colorless, often with membranous 

 expansions at the joints; spores very minutely and closely spinulose, 

 pale purplish gray, 10-15 /jl. Plasmodium white, then violet. 



Distinguished from D. effusum by the larger spores and coarser 

 capillitium. 



Iowa; Europe, Ceylon, Malay Peninsula, Japan. 



4. Diderma subdictyospermum (Rost.) Lister 



Mycetozoa ed. 2. 101. 1911. 



1876. Chondrioderma subdictyospermum Rost., Mon. App. 16. 

 1892. Chondrioderma dealbatum Mass., Mon. 207. 



Sporangia crowded, sessile on a white hypothallus, subglobose or 

 hemispherical, 0.3-0.5 mm. in diameter, white; outer sporangium wall 

 thick, fragile, crustose, closely adhering to the membranous inner 

 layer; columella hemispherical or subglobose, white; capillitium dark 

 purplish, rigid, sparingly branched; spores purplish brown, marked 

 with prominent raised ridges or broken reticulations, about 12 ju. 



The type in the British Museum is labelled Didymium dealbatum 



