CHONDRIODERMA.] PHYSARACE.E. 77 



globose, sessile, crowded, O5 to 1 mm. diarn., seated usually on a 

 strongly developed white hypothallus, smooth or rugose, white ; 

 sporangium -wall of two layers, the outer thick, fragile, composed 

 of globular lime-granules 1 to 2 /JL diarn., often crumbling away 

 from the membranous, more persistent inner layer, sometimes 

 inseparable. Columella convex or hemispherical, white or pale 

 flesh-coloured. Capillitium of slender, flexuose, purplish threads, 

 branching at an acute angle and somewhat anastomosing. Spores 

 violet-brown, spinulose, 8 to 11 /A diam. Cooke, Myx. Brit., 

 p. 38. Didymium spumarioides Fr., Symb. Gast., p. 20 (1818) ; 

 Mass., Mon., p. 232. Physarum stromateum Link, Handb., iii., 

 p. 409 (1833). Chondrioderma stromateum Rost., Mon., App., 

 p. 18. Chondrioderma virgineum Mass., Mon., p. 207. 



Plate XXIX., B. a. sporangia, x 20 ; b. capillitium, with fragment of 

 sporangium-wall and spores, x 280 ; c. spore, x 600 (England). 



The type specimen of C. virgineum Mass. (K. 560) is a frequent 

 form of C. spumarioides without hypothallus ; the capillitium in some 

 sporangia is normal and without expansions. The type specimen of 

 C. stromateum Rost. in the Strassb. Herb, is from Lochem (leg. Spree, 

 Rab. Fung. Eur., 432) ; a part of this gathering is in the British 

 Museum (B. M. 515) ; it does not appear to present any character by 

 which it can be separated from C. spumarioides. 



Hub. On dead leaves,etc. Common. Lyme Regis,Dorset (L :B.M.52) ; 

 France (K. 37) ; Germany (B. M. 515); New "York (B. M. 886); 

 Mass., U.S.A. (L:B.M.52). 



2. C. subdictyospermum Rost., Mon., App., p. 16 (1876). 

 Plasmodium 1 Sporangia subglobose, sessile, crowded, 0'3 to 

 0'5 mm. diam., snow-white, seated on a well-developed white 

 hypothallus; sporangium -wall thick, fragile, composed of an 

 outer crust of globular lime-granules 2 /x diam., with a delicate, 

 membranous, inseparable inner layer. Columella hemispherical 

 or subglobose, white. Capillitium of somewhat rigid, violet-brown, 

 sparingly branched threads. Spores violet-brown, reticulated 

 with raised ridges or with broken bands, forming a margin about 

 2 /JL broad; 10 to 12 ^ diam. Didymium dealbatum Berk. & 

 Curt., in Herb. Chondrioderma dealbata Mass., Mon., p. 207. 



Plate XXX., B. d. sporangia, x 20 ; e. capillitium and spores, x 280 ; 

 /. spore, x 600 (Venezuela, Rostafinski's type) ; g. spore, x 600 (Cape). 



This species appears to be allied to C. spumarioides, differing 

 essentially in the spores. It is represented by two gatherings. One 

 is from Venezuela, named Didymium dealbatum Berk. & Curt. 

 (B. M. 570 ; K. 1522) ; this is the type given by Rostafinski (Mon., 

 App., p. 16), and accurately described as having spores provided with 

 protuberances either irregularly disposed or combined into an incomplete 

 net. The other gathering is in the Kew collection (K. 466), named 

 Didymium pJujsaroides, Cape 198 ; in this specimen the spores are more 

 perfectly reticulated, and, except in colour, resemble those of Trichia 

 favoginea Pers. ; the capillitium is also more flexuose. 



Hab. On moss. Cape (K. 466) ; Venezuela (B. M. 570). 



