58 ENDOSPOREAE [PHYSARUM 



20. P. polycephalum Schwein. Syn. Fung. Carol., 

 63 (1822). Plasmodium occurring in masses of decaying 

 leaves or in rotten logs ; at first colourless, as it emerges 

 for fructification white, then yellow, spreading far over 

 all adjacent objects (Macbride). Total height 1-5 to 2 mm. 

 Sporangia stalked, compressed vertically, lenticular, un- 

 dulate or lobed, confluent in clusters of 5 to 10 together, 

 grey or yellow ; sporangium- wall membranous, with 

 scattered thin included clusters of white or yellow lime- 

 granules. Stalks subulate, slender, inclined, usually fascicu- 

 late, 5 to 10 combined, yellow or tawny, translucent, without 

 deposits of lime. Columella none. Capillitium a loose net- 

 work of slender threads with many flat expansions at the 

 axils ; lime-knots yellow, very variable in shape, size, and 

 abundance. Spores violet-brown, minutely spinulose, 8 to 

 10 fx diam. — Didymium 'polycephalum Fries Syst. Myc, iii. 

 122 (1829). D. polymorphum Mont, in Ann. Sci. Nat., 

 ser. 2, viii. 361 (1837). D. gyrocephalum Mont. I.e., 362. 

 D. luteogriseum Berk. & Curt, in Grev., ii. 65 (1873). Phy- 

 sarum polymorphum Rost. Mon., p. 107 (1875) ; Mass. Mon., 

 283 ; Lister Mycetozoa, 48. Tilmadoche gyrocephala Rost. 

 I.e., p. 131 (1875) ; Mass. Mon., 335. T. polycephala Macbr. 

 N. Am. Slime-Moulds, 57 (1899). 



Var. obrusseum Lister : sporangia single, not united in 

 clusters. — Didymium obrusseum Berk. & Curt, in Journ. 

 Linn. Soc, x. 348 (1869). D. tenerrimum Berk. & Curt. I.e. ; 

 Mass. Mon., 247. Physarum obrusseum Rost. Mon., App. 

 p. 11 (1876) ; Macbr. N. Am. Slime-Moulds, 52. 



PI. 34. — a. yellow and grey sporangia (Philadelphia) ; b. capillitium and spores ; 

 c. spore. 



The description given by Schweinitz of Physarum polycephalum is 

 sufficiently good to leave no doubt as its referring to the present 

 species ; this name therefore takes precedence over Physarum poly- 

 morphum (Mont.) Rost. The four specimens referred to in Rostafinski's 

 Monograph under the latter name, from Cuba, S. Carolina, New Jersey, 

 and Pennsylvania, are in the Kevv Herbarium. The type of Tilmadoche 

 gyrocephala (Mont.) Rost. from Brazil appears to have been lost, but 

 from Rostafinski's excellent description it clearly must be assigned 

 to the present species. The type of Didymium obrusseum Berk. & Curt., 

 no. 532 Fung. Cub. (B.M. 440) has much compressed and undulated 

 sporangia, similar to the simple sporangia frequently met with in 

 P. polycephalum. The colour of the sporangia varies from grey to yellow 

 in the same gatherings. 



Hob. On dead wood, etc. — Pennyslvania (B.M. 860) ; Iowa (B.M. 

 1227) ; Ohio (B.M. 1225) ; Brazil (B.M. 2135) ; Borneo (B.M. 2138) ; 

 Japan (B.M. 2137) : var. obrusseum — Cuba (B.M. 440). 



21. P. flavicomum Berk, in Hook. Loud. Journ. Bot., 

 iv. 66 (1845). Plasmodium yellowish-green (teste Ravenel). 

 Total height 1-2 to 1-75 mm. Sporangia subglobose, or 



