Didymium.] BRITISH MYCETOZOA. 25 



2. D. dubium Rost. — Sporangia thin, flat, roundish, white; 

 lime-crystals stellate, adhering to form a frosted crust often extending 

 beyond the margin of the broad membranous base of the sporangium. 

 Columella none. Capillitium profuse, of rigid purple-brown, erect 

 anastomosing threads, slender above and below. Spores violet-grey, 

 nearly smooth, 8 to 15/1 diam. 



Hab. On dead leaves. 



3. D. Serpula Fr. — Sporangia thin, effused, grey plasmodiocarps. 

 Columella none. Capillitium of slender threads connected with 

 large scattered purplish vesicles, 20 to 50 //. diam., filled with 

 yellowish granular matter. Spores pale violet-brown, nearly smooth, 

 7 to 9 fi diam. 



Hab. On dead leaves, etc. 



4. D. Clavus Rost. — Sporangia disc-like, grey, on a darker 

 central stalk ; in shape resembling a flat-headed nail. Columella 

 none. Capillitium profuse. Spores pale violet-brown, almost smooth, 

 6 to 8 fj. diam. 



Hab. On dead leaves. 



5. D. farinaceum Schrad. — Sporangia hemispherical, deeply 

 umbilicate beneath, grey; sporangium-wall mottled with brown. 

 Stalk and broad columella dark opaque-brown. Capillitium of 

 coarse pale or dark threads. Spores dark purplish-grey, nearly 

 smooth, 9 to 1 1 jjl diam. 



Var. minus is smaller, with short stalks and slender capil- 

 litium ; spores 7 to 9 //. diam. 



Hab. On dead leaves, bark, etc. 



6. L. nigripes Fr. — Distinguished from D. farinaceum, var. 

 minus, in the stalk being longer and more slender, and in being 

 horn-clear instead of opaque and granular. 



Var. xanthopus Fr. has an orange stalk and white columella. 

 Hab. On dead leaves. 



7. D. effusum Link. — Sporangia very various, subglobose, 

 hemispherical, stalked, sessile, or effused plasmodiocarps, white or 

 grey; the stellate crystals adhering to form a wrinkled crust, or 

 scattered ; stalk short, white, opaque, sometimes orange. Columella 

 white. Capillitium colourless or dark. Spores violet-brown, 

 spinulose, 8 to 1 1 /x diam. 



Hab. On dead leaves. 



8. D crustaceum Fr. — Distinguished from D. effusum by the 

 sporangia being often clustered and reniform, and by their being 

 enclosed in a thick, smooth, fragile, globose crust of loosely adhering 

 large crystals, and in the more strongly spinulose spores, 10 to 13 //. 

 diam. 



Hab. On dead leaves, etc. 



