physarum] physaraceae 79 



work this species was referred to P. Diderma Rost. ; a subsequent more 

 complete translation of Rostafinski's description shows P. Diderma 

 to have had crowded globose sporangia, characters inapplicable to the 

 present species, for which therefore a new name, P. bitectum, is here 

 adopted. In the absence of the type from Warsaw, the position of 

 P. Diderma remains uncertain, but the description applies fairly to 

 P. didermoides var. lividum. 



Hab. On dead leaves, twigs, etc.- — Wanstead, Essex (B.M. 1250) ; 

 Norfolk (B.M. 2296); Flitwick, Beds (B.M. 1251); Germany (B.M. 

 512) ; S. France (B.M. 2297) ; Portugal (B.M. 2298) ; Washington 

 State (B.M. 2299); Colorado (B.M. 2301); California (B.M. 2300); 

 Venezuela (B.M. 2302). 



49. P. testaceum Sturgis in Colorado Coll. Publ., Sci. 

 Ser., xii. 18 (1907). Plasmodium ? Sporangia sessile, white, 

 subglobose, clustered and polygonal from mutual pressure, 

 - 7 mm. diam. ; outer sporangium-wall white, eggshell-like, 

 separating from the membranous colourless inner wall. 

 Capillitium consisting of numerous large and small angular 

 branching white lime-knots connected by short hyaline threads. 

 Spores purplish-brown or greyish -purple, spinulose, distinctly 

 darker and more spinulose on one side, 8 to 10 /x diam. — 

 P. didermoides var. lividum Lister in Journ. Bot., xxxvi. 162 

 (1898), in part. 



PI. 54. — a. Sporangia (Colorado) ; b. capillitium and spores ; c. spore. 



This species is closely allied to P. didermoides var. lividum, from 

 which it differs in the double sporangium-wall and the large branching 

 lime-knots ; it has hitherto been recorded only from the United States, 

 where it appears to be widely distributed and not infrequent. 



Hab. On dead wood —Maine (B.M. 1595) ; Vermont (B.M. 2303) ; 

 Massachusetts (B.M. 2305) ; Ohio (B.M. 2304) ; Colorado (B.M. 2058). 



50. P. contextum Pers. Syn., 168 (1801). Plasmodium 

 yellow. Sporangia sessile, subglobose, ovoid, erect, 04 to 

 0-6 mm. diam., or reniform and elongated on a broad base, 

 crowded, often angled by mutual pressure, rounded or flattened 

 above, smooth, yellowish-white or ochraceous ; sporangium- 

 wall double, the outer layer cartilaginous, usually with 

 dense deposits of lime, often breaking away in the upper 

 part from the thin inner layer. Columella none. Capillitium 

 with scanty hyaline threads and numerous large irregularly 

 branching white lime-knots. Spores dark violet-brown, 

 spinulose, 10 to 13 /j. diam. — Rost. Mon., p. 109 ; Macbr. 

 N. Am. Slime-Moulds, 31. Diderma contextum Pers. Obs. 

 Myc, i. 89 (1796). D. ochroleucum Berk. & Curt, in Grev., 

 ii. 52 (1873). D. flavidum Peck in Rep. N.Y. State Mus., 

 xxviii. 54 (1879). Physarum conglomeratum Mass. Mon., 

 304 (1892). Lycoperdon luteum Jacq. Misc., 138, t. 8 (1778) ? 

 Leocarpus contextus Fr. Summ. Veg. Scand., 450 (1849). 



Pi. 55. — a. sporangia (Surrey); b. capillitium and spores, with fragment of 

 sporangium-wall ; c. spore. 



