58 ENDOSPORE-E. fPHTSARUM. 



The uncompressed sporangia with the outer wall nearly free from 

 the smooth purplish inner wall characterises this species, and dis- 

 tinguishes it from P. bivalve and P. compressum, its nearest allies. 



ITab. On dead leaves, etc.— Wanstead, Essex (L;B.M.34) ; Plitwick, 

 Beds. (L:B.M.34) ; Germany (B. M. 512). 



26. P. contextum Pers., Syn., p. 168 (1801). Plasmodium 

 yellow. Sporangia subglobose, ovoid, erect, 04 to 0-6 mm. diam., 

 sessile 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 thick with dense deposits of lime, often breaking ^.way in 

 the upper part from the thin colourless inner layer. Columella 

 none. CapiUitium with scanty hyaline threads and numerous 

 large irregularly branching white lime-knots. Spores dark violet- 

 brown, spinulose, 10 to 13 /a diam. — Host., Mon., p. 109 ; Cooke, 

 Myx. Brit., p. 13; Mass., Mon., p. 303 (in part); Macbride, in 

 Bull. Nat. Hist. Iowa, ii., p. 157. Biderma contextum Pers., Obs. 

 Myc, i., p. 89 (1796); Fr., Syst. Myc, iii., p. 111. Biderma 

 ocfiroleucwm Berk. & Curt., in Grev., ii., p. 52. Physarwm con- 

 ghmeratum Mass., Mon., p. 304. 



Plate XX., A. — a. sporangia of two forms, x 20 ; J. capillitinm and spores, 

 X 280 ; c. spore, x 600 (Germany : Rostafinski's type). 



The type of Diderma ochroleucum Berk. & Curt., from Pennsylvania 

 (K. 1533), is typical P. contextum. 



Eah. On dead leaves, sticks, etc. — Lyme Regis, Dorset (L:B.M.35); 

 near Birmingham (L:B M.36) ; France (K. 365) ; Germany (B. M. 418) ; 

 Sweden (K. 1277) ; Poland (Strassb. Herb.) ; Iowa (B. M. 808); 

 Mass., U.S.A. (L:B.M.35). 



27. P. conglomeratum Eost., Mon., p. 108, figs. 73, 79, 90 

 (1875). Plasmodium ? Sporangia subglobose, sessile on a broad 

 base, densely aggregated on one plane, angled by mutual pressure, 

 0-3 to 0'5 mm. broad, yellow or brownish- white, mottled with 

 paler shades; sporangium- wall double, the inner layer of the 

 convex upper wall having translucent, pale yeUow, curved, 

 thickened areas, with a vitreous fracture ; the outer layer thick, 

 consisting of easily crumbling yellow lime-granules ; the wall 

 below thin with the two layers less distinct. Capillitium of deli- 

 cate branching hyaline threads, with numerous white or yellowish, 

 branching, often confluent lime-knots. Spores pale violet-brown, 

 almost smooth, 8 to 10 /* diam. — List., in Journ. Bot. 1891, 

 p. 259, PI. cccviii., fig. 1. Diderma conglomeratxmn Pr., Syst. Myc, 

 iii., p. Ill (1829). P.hysarum Rostafinskii Mass., Mon., p. 301. 



Plate XX., B. — a. sporangia, x 20; 5. capillitium, with fragment of 

 sporanguim-wall, showing vitreous structure (J') and spores, x 280 ; c. spore, 

 X 600 (Germany : Eostafinski's type). 



Distinguished from P. contextum by the pale, nearly smooth and 

 smaller spores, and by the vitreous structure of the inner wall of the 

 upper part of tho sporangium. Rostafin-ski's type specimens of P. 

 conglomeratum from Germany (Strassb. Herb.) and from Sikkim 



