PHYSARUM.] PHYSARACE.E. 41 



from Dr. Rex (L:B.M.12) marked "P. Petersii var. Farlomi, con- 

 globate form," the sporangia are in clusters of from 6 to 14 together, 

 as in the compound forms of P. polymorplium. 



Hab. On dead wood. Poland (Strassb. Herb) ; Africa (K. 74) ; 

 Bonin Island (K. 333); Borneo (L:B.M.12) ; Ohio (L:B.M.12) : 

 Iowa (B.M. 1012, 1015); Georgia (B.M. 853B) ; conglobate form, 

 Philadelphia (L:B.M.12). 



3. P. pulehripes Peek, in Bull. Buff. Soc. N. Hist., i., p. G4 

 (1873). Plasmodium ? Total height 1 to 2 mm. Sporangia 

 globose, stipitate, yellow-orange, orange-red to dark brown, 

 sometimes grey from, the absence of lime, about 0'5 mm. diam. ; 

 sporangium -wall membranous, with deposits of lime usually 

 abundant, sometimes scanty. Stalk vermilion-red or red-brown, 

 0'5 to 1*5 mm. long, 0*1 mm. thick, somewhat narrowed upwards, 

 densely charged with red or brown lime-granules, brittle. 

 Columella conical. Capiliitium with red or brown lime-knots, 

 in other respects as in P. globuliferum. Spores violet --brown, 

 almost smooth, 6 to 8 /A diam. Mass., Mon., p. 315. Didymium 

 erythrinum Berk., in Grev., ii. (1873), p. 52 ; Mass., Mon., p. 249. 

 Didymium Ravenelii Berk. & Curt., in Grev., ii. (1873), p. 53 ; 

 Physarum Ravenelii Mass., Mon., p. 281. 



Plate VII., A. a. sporangia, x 20 ; b. capillitium and spores, x 280; 

 c. spore, x 600 (United States). 



A frequent species in the United States, differing from P. globuli- 

 ferum chiefly in the colour of the lime ; and this character appears to 

 be constant. Under P. pulehripes are included Didymium erythrinum 

 Berk, and D. Ravenelii Berk. & Curt., which Rostafinski in the 

 Appendix to his Mon., p. 8, has placed under Physarum psittacinum, 

 a species without colnrnella and without lime-granules in the stalk. 

 Examination of the types in the Kew collection shows that the 

 sporangia of D, t'ry('/rt/i>/,>i (K. 1205) are immature, but those of D. 

 Ravenelii (K. 1513 and B.M. 560) possess a well-developed coluinella, 

 and the stalks in both types are densely charged with lime-granules. 



The type of P. Pcfcrxti. Berk. Curt, in Grev., ii., p. 66 (1873) ; Host., 

 Mon., A pp., p. G (K. 1254), belongs also to P. pnlcln-iprx. So much 

 confusion lias been caused by Berkeley and Curtis in giving different 

 names to different gatherings of this species, and by Rostafinski in 

 placing P. globuliferum as a variety of P. Petersii, that Peck's name is 

 adopted as being free from ambiguity. 



Hab. On dead wood. - -Massachusetts (L:B.M.13) ; Ohio (L: 

 B.M. 13) ; N. Carolina (B. M. 569, 852A). 



4. P. murinum Lister sp. nov. Plasmodium ? Sporangia globose, 

 about 0'5 mm. diam., stalked or sessile and forming plasmo- 

 diocarps, pinkish or yellowish brown, rugose ; sporangium- wall 

 membranous, with innate clusters of brown lime-granules. Stalk 

 erect, 0'5 mm. long or shorter, O'l mm. thick, of equal breadth 

 throughout ; pale brown, furrowed, containing dense deposits of 

 white lime-granules. Columella present in the stalked forms, 

 conical. Capillitium forming either a dense network of obtusely 

 branching hyaline threads, persistent after the dispersal of the 



