104 ENDOSPOREAE [DIDERMA 



Veg. Scand., 451 (1849). Chondrioderma spumarioides Rost. 

 Mon., p. 174 (1875) ; Lister Mycetozoa, 76. C. stromateum 

 Rost. Mon., App. p. 18 (1876). C. virgineum Mass. I.e., 

 207 (1892). Diderma cinereum Morg. Myx. Miami Valley, 

 70 (1894) ; Macbr. N. Am. Slime-Moulds, 101. D. stromateum 

 Morg. I.e., 68. 



PI. 84. — a. sporangia (England) ; b. capillitium and spores with fragment of 

 sporangium-wall ; c. spore. 



This species is closely allied to D. globosum with which it is connected 

 by intermediate forms ; it differs in having the layers of the sporangium- 

 wall more closely connected and in the smaller smoother spores. The 

 latter, being a microscopic character, could not be observed by the 

 earlier authors, who probably confused the two species. The type 

 of C. virgineum Mass. from Hampstead, Middlesex (K. 560), is a form of 

 D. spumarioides without hypothallus ; the capillitium in some sporangia 

 is normal, in others there are the expansions described by Massee. 

 The specimen named G. stromatexim by Rostafinski in the Strassb. 

 Herb, from Lochem (leg. Spree, Rab. Fung. Eur., no. 432, B.M. 515) ; 

 does not present any character by which it can be separated from the 

 present species. In gatherings made by Mr. Petch in Ceylon the mature 

 sporangia have their walls cracked into concave polygonal areolae, 

 whose edges form polygonal ridges (see Petch in Ann. Perad., iv. 343) ; 

 a similar mode of dehiscence occurs in a gathering made by Mr. A . F. 

 Blakeslee in Venezuela (B.M. 2391) ; in other respects these specimens 

 are typical of the present species. 



Hab. On dead leaves. Common in the British Isles. — Lyme Regis, 

 Dorset (B.M. 1287); Wanstead Park, Essex (B.M. 2384); Flitwick, 

 Beds (B.M. 2385) ; North Wales (B.M. 2386) ; Ireland (B.M. 2387) ; 

 Sweden (B.M. 2388) ; France (K. 37) ; Germany (B.M. 515) ; Portugal 

 (B.M. 2389); Ceylon (B.M. 2390); New York (B.M. 886); New 

 Hampshire (B.M. 1288) ; Washington State (B.M. 2393) ; Colorado 

 (B.M. 2392) ; Antigua (B.M. 1660) ; Venezuela (B.M. 2391). 



5. D. globosum Pers. in Roemer N. Mag. Bot., i. 89, t. iv, 

 figs. 4, 5 (1794). Plasmodium white. Sporangia globose, 

 sessile, crowded, 0-5 to 0-8 mm. diam., smooth, white or 

 cream-coloured ; usually seated on a strongly developed white 

 or cream-coloured hypothallus ; sporangium-wall of two layers, 

 the outer eggshell-like, composed of globular lime-granules 

 1 to 2 /x diam., often separating widely from the membranous 

 inner layer. Columella hemispherical or subglobose, usually 

 minute, white or pale flesh-coloured. Capillitium consisting 

 of slender irregularly branched and anastomosing pale 

 purplish threads, often with irregular expansions towards the 

 base enclosing a few lime-granules. Spores dark purplish- 

 brown, spinulose, 10 to 14 fx diam. — Macbr. N. Am. Slinie- 

 Moulds, 97. D. crustaceum Peck in Rep. N. York Mus., xxvi. 

 74 (1874) ; Macbride I.e., 98. Didymium candidum Schrad. 

 Nov. PI. Gen., 25 (1797) ? D. globosum Chev. Fl. Paris, i. 

 •534 (1826) ? Chondrioderma globosum Rost. Mon., p. 180 

 (1875); Mass. Mon., 206; Lister Mycetozoa, 78. C. affine 



