50 ENDOSPOREAE [PHYSARUM 



This specific name had its origin in Physarum aurantium B rufipes 

 Alb. & Schw. (Consp. Fung., 94, 1805), = Diderma rufipes Fr. Syst. 

 Myc, iii. 101 (1829), = P. Schumacheri var. rufipes Rost. Mon., App. 

 p. 7. The single German gathering described under these names 

 has long since disappeared ; in the original description Albertini and 

 Schweinitz make no mention of the presence or absence of lime in the 

 stalk ; the sporangia are said to be globose or obovate, to be provided 

 with a spurious central columella, and to have been found " on a heap of 

 dead leaves, twigs, etc." ; these characters are not appropriate to P. pid- 

 chripes, a species which appears always on dead wood, and has been 

 recorded hitherto with certainty only from the United States. What 

 P. aurantium B rufipes Alb. & Sch. really was remains a matter for 

 conjecture ; Rostafinski states that he had not seen the type specimen. 

 It would seem better therefore to drop the specifi.* name rufipes. The 

 type of Didymium erythrinum Berk. (K. 1265) is somewhat immature, 

 but shows the opaque red-brown stalks densely charged with lime 

 throughout characteristic of P. pidchripes ; it was wrongly placed by 

 Rostafinski under P. psittacinum (Mon., App. p. 8), a species without 

 columella, and with translucent stalks free from lime granules. The 

 type of Didymium Ravenelii Berk. & Curt, from North Carolina (B.M. 

 1738) is a form of the present species 'with red-brown stalks, columellae 

 and lime-knots. The type of P. Peter sii Berk. & Curt, from Alabama 

 (K. 1254) is also identical with P. pulchripes. Peck's name is here 

 adopted as being free from ambiguity. 



8. P. murinum Lister Mycetozoa, 41 (1894). Plasmodium? 

 Sporangia globose, about 0-5 mm. diam., stalked or sessile and 

 forming plasmodiocarps, pale pinkish or greyish brown, rugose ; 

 sporangium-wall membranous, with included clusters of brown 

 lime-granules. Stalk erect, 05 mm. long or shorter, 0-1 mm. 

 thick, of equal breadth throughout, brown, furrowed, contain- 

 ing dense deposits of white or brown lime-granules. Columella 

 present only in the stalked forms, conical. Capillitium 

 forming either a dense network of widely branching hyaline 

 threads, persistent after the dispersion of the spores, with 

 ovoid brown lime-knots, or a looser network of hyaline 

 threads, with numerous elongated irregularly branching lime- 

 knots. Spores pale brownish- violet, nearly smooth, 8 to 10 p. 

 diam. — P. Braunianum Lister in Journ. Bot., xxix. 259(1891) 

 (non Rost). P. Ravenelii Macbr., N. Am. Slime-Moulds, 48 

 (1898) (non Mass). Cytidium Ravenelii Morg. Myx. Miami 

 Valley, 82 (1896). 



PI. 18. — a. sporangia; b. capillitium and spores; c. spore; (Philadelphia). 



This species is closely allied on the one hand to P. globuliferum 

 and on the other to P. pulchripes ; it is distinguished from both by 

 the brown colour of the sporangium, lime-knots and stalk. 



Hob. On dead leaves and wood. — North Wales (B.M. 2106), 

 Moffat, Scotland (B.M. slide) ; Sweden (B.M. 2107) ; Switzerland 

 (Zurich Herb.) ; Philadelphia (B.M. 1204) ; Ohio (B.M. 1203). 



9. P. pulcherrimum Berk. & Rav. in Grev., ii. 65 (1873). 

 Plasmodium? Total height 1 mm. Sporangia stalked, 



