198 ENDOSPORE^E. 



Hob. On dead wood and bark. Epping Forest, Essex (L:B.M.164) ; 

 Lyme Regis, Dorset (L-.B.M.164) ; Leicestershire (B. M. 690) ; Glamis, 

 Scotland (B. M. 323) ; Belgium (B. M. 6 ( JO) ; Germany (B. M. 688) ; 

 Italy (B. M. 689) ; Poland (Strassb. Herb.) ; Australia (K. 153) ; 

 Philadelphia (L:B.M.164j ; Ohio (L:B.M.1G4) ; S. Carolina (B. M. 

 697, 986). 



3. P. populina Fries, Symb. Gaster.,p. 12 (1817). Plasmodium 



watery-grey, in decaying bark. Sporangia globose, depressed, 



ellipsoid, or forming short broad plasrnodiocarps, crowded, sessile 



on a broad or narrow base, rarely substipitate, 0'5 to 1 mm. 



diam., dark purple or purplish-brown, nut-brown, grey or white, 



dehiscing along definite lines, either horizontally with a convex 



lid or in broad sinuous lobes ; sporangium -wall of two layers, the 



outer cartilaginous, opaque, charged with brown granular matter 



intermixed with acicular or angular calcareous deposits which 



form a pruinose or crystalline covering in the grey and white 



sporangia ; inner layer membranous, usually closely combined 



with the outer. Capillitium scanty or almost wanting, consisting 



of slender, branched or simple, yellow threads, 1*5 to 4 /x, diam., 



irregularly compressed, angled and constricted, minutely warted, 



rarely smooth ; attached to the sporangium-wall or free. Spores 



yellow, more or less minutely warted, 12 to 14 /x diam. 



Lycoperdon corticate Batsch, Elench. Fung., p. 155 (1783). 



Perichcena corticalis Host., Mon., p. 293, fig. 188 ; Cooke, Myx. 



Brit., p. 78 ; Zopf, in Schenk, Handbuch der Botanik, iii., 2, 



p. 169; Blytt, Bidr. K. Norg., Sop. iii. (1892), p. 10; Macbride, 



in Bull. Nat. Hist. Iowa, ii., p. 120; Mass., Mon., p. 115. 



Trichia fusco-atra Sibth., Fl. Oxon, p. 407 (1794). Perichcena 



fusco-atra Host., Mon., p. 294; Cooke, Myx. Brit., p. 78. 



Licea pannorum Cienk. (non Wallr.), Pringsh., Jahrb., iii., p. 407. 



Perichcena liceoicles Host., Mon., p. 295; Mass., Mon., p. 118. 



Oligonema Broomei Mass., in Journ. K. Micr. Soc. (1889), 



p. 346 ; Mass., Mon., p. 172. 



Plate LXXIL. A. a. sporangia, x 20 ; b. capillitiurn and portion of 

 sporangium-wall, x 280 ; c. capillitium and spore, x 600 (England). 



In large developments from one plasmodium on the inner side of 

 the bark of old stumps, every variety of form is sometimes represented, 

 from broad plasmodiocarps to globose and substipitate sporangia, and 

 the colour may range from deep purple to grey. In gatherings where 

 the colour is pure white, the outer layer of the sporangium-wall 

 consists of crystalline deposits of lime without the intermixture of 

 brown granules. The capillitium is subject to much variation according 

 to the season of the year and other causes. In a gathering at Lyme 

 Regis in the autumn, the capillitium was scanty, forming a net of 

 rugged coarsely warted threads 2 to 4 /z diam., with a few scattered 

 free threads ; in the following spring another growth on the same 

 pieces of bark had sporangia of a similar shape and colour, but with 

 a more abundant capillitium forming a freely branching slender net- 

 work of minutely warted threads 1 to 1*5 /x diam., scarcely differing 

 from that of P. dcpresxa, the larger spores being the chief character 

 which distinguished the gathering from that species. The specimens 



