40 ENDOSTORE/E. [PHYSARUM. 



which are 10 to 50 /x broad and tilled with globular lime-granules, 

 1 to 1'5 /x (Ham. Spores violet-brown, minutely spinulose, 7 to 10 

 fji diam. Host., Mon., p. 101 ; Cooke, Myx. Brit., p. 12 ; Mass., 

 Mon., p. 287 (in part) ; Macbride, in Bull. Nat. Hist. Iowa, ii., 

 p. 156. Didymium leucopus Fr., Syst. Myc., iii., p. 121. 



Plate VI., A. a. sporangia, x 20 ; b. capillitium with fragment of spo 

 rangium-wall and spores, x 280 ; c. spore, x 600 (England). 



The snow-white nearly smooth stalk, which is chalk-white in section 

 to the base, always distinguishes P. leucopus from P. nutans. The 

 lax capillitium, with large lime-knots and the large lime-granules 

 in the knots and sporangium- wall, separate it from P. globuliferum , 

 which is its nearest ally. The types quoted by Rostafinski from 

 Germany and Russia of this well-marked species "are not represented 

 in the Strassburg or British collections ; the stations here given are 

 therefore confined to those of the English and American gatherings. 

 It is not common ; the only specimen in the Kew collection (K. 518), 

 leg. J. Henderson, is named Didymium squamulosum. 



Hab. On dead leaves, moss, etc. Batheaston, Somerset (B.M. 48) ; 

 Lyme Regis, Dorset (L:B.M.ll) ; Ohio (L:B.M.ll) ; New Granada 

 (Paris Herb.). 



2. P. globuliferum Pers., Syn., p. 175 (1801). Plasmodium ? 

 Total height 1 to 1'5 mm. Sporangia globose, stipitate, erect, 

 white, gregarious, 0'5 mm. diana. ; sporangium-wall membranous, 

 with crowded clusters of innate lime-granules. Stalk white or 

 pale buff, sometimes red-brown towards the base, 0'5 to 1 mm. 

 long, '05 to '01 mm. thick, nearly smooth, brittle, chalky in section. 

 Columella conical. Capillitium persistent, retaining the form of 

 the sporangium after the dispersion of the spores, forming a close 

 network of obtusely branching hyaline threads with numerous 

 fusiform or rounded, white, or pale ochraceous lime-knots 10 to 

 20 /x diam. ; the lime-knots are not usually developed at the 

 axils of the branches, which are flat and triangular, or if 

 present, usually minute. Spores violet-brown, almost smooth, 

 6 to 8 /x diam. Host., Mon., p. 98, fig. 86 ; Mass., Mon., p. 297. 

 Sphcerocarpus ylobuliferus Bull., Champ., p. 134, PI. 484, fig. 3 

 (1791). Physarum Petersii Berk. & Curt., var. a. Farlowii Rost., 

 Mon., App., p. 6. Physarum albicans Peck, in Rep. New York 

 Mus., xxx., p. 50; Mass., Mon., p. 312. Didymium Barteri 

 Mass., Mon., p. 231. Physarum columbinum Macbride, in Bull. 

 Nat. Hist. Iowa, ii., p. 384. 



Plate VI., B. a. sporangia, x 20, in two the sporangium-wall has fallen 

 away, leaving the persistent head of capillitium ; b. stalks showing the 

 columella after the capillitium has broken away, x 20 ; c. capillitium, 

 columella, and spores, x 280; d. spore, x 600 (United States). 



The types of P. Petersii var. a Farlowii Rost., and P. albicans Peck 

 are the same species as the type of P. globuli/erum in the Strassburg 

 collection. P. columbinum Macbride, from Iowa (B.M. 1012), is also 

 P. globul/fcrum ; it has snow-white, occasionally red-brown, stalks, 

 and well-developed conical columella?. Didymiuin Barteri Mass. (K. 74) 

 appears to have been rightly named by Rostafinski "7\ globuliferum, 

 immaturum" ; the specimen is obscured by mould. In the specimen 



