didymium] didymiaceae 129* 



Hob. On dead leaves, twigs, etc. Common. — Batheaston, Somerset 

 (B.M. 80); Epping Forest, Essex (B.M. 1331); Lyme Regis (B.M. 

 1332) ; near Aberdeen (B.M. 2473) ; Germany (Strassb. Herb.) ; 

 Portugal (B.M. 2474) ; Ceylon (B.M. 537) ; Java (B.M. 2475) ; 

 Philippine Islands (B.M. 2035) ; New York (B.M. 1881) ; Philadelphia 

 (B.M. slide) ; Antigua (B.M. 1664). 



7. D. melanospermum Macbr. N. Am. Slime-Moulds, 88 

 (1899). Plasmodium colourless or grey. Total height 0-5 to 

 1 mm. Sporangia gregarious, subglobose or hemispherical, 

 deeply umbilicate beneath, 0*7 to 1 mm. diam., either stalked 

 or sessile, often confluent, white or grey ; sporangium-wall 

 firm, mottled with purple-brown and beset with stellate 

 crystals of lime. Stalk cylindrical from a broad base, striate, 

 dark brown, rarely rufous, 02 to 07 mm. long, 005 to 0-2 mm. 

 thick, opaque and granular from enclosed refuse matter, 

 sometimes containing crystalline nodules of lime. Columella 

 large, hemispherical, umbilicate, dark brown, rarely whitish, 

 chambered, containing irregular nodules of lime. Capillitium 

 of stout sparingly branched or simple more or less flexuose 

 threads, colourless or purplish- brown, often showing dark caly- 

 ciform thickenings. Spores dark purplish-brown or purplish- 

 grey, with a thick spore-wall, nearly smooth or spinose, 9 to 

 12 jx diam. — Physarum melanospermum Pers. in Roemer N. Mag. 

 Bot., 88 (1794). P. farinaceum Pers. Syn., 174 (1801). P. 

 cinerascens Schum. Enum. PI. Saell., ii. 199 (1803) ? P. globosum 

 Schum. I.e., 203 ? P. sinuosum Link in Mag. Ges. Nat. Fr. 

 Berl., hi. 27 (1809). P. capitatum Link I.e. P. nigrum Fr. Syst. 

 Myc, hi. 146 (1829) ? Didymium farinaceum Schrad. Nov. 

 Gen. PI., 26, t. 5, fig. 6 (1797) ; Rost. Mon., p. 154 ; Mass. 

 Mon., 219 ; Lister Mycetozoa, 97. D. complanatum Schrad 

 I.e., 24, t. 5, fig. 5 ? D. lobatum Nees Syst., 112 (1816) ? ; 

 Fr. Syst. Myc, iii. 123. D. physaroides Fr. Symb. Gast., 21 

 (1818) ; Rost. Mon., p. 158 ; Mass. I.e., 233. D. melanopus 

 Fr. Syst. Myc. iii. 114 ? D. Fairmani Sacc. Journ. Myc, 1889, 

 79, & Fairman Contr. Myc. West N.Y., 52, t. hi., figs. 7 to 9. 

 Trichia compressa Trentep. in Roth Catal. Bot., i. 229 (1797). 

 T. farinosa Poiret in Lam. Encycl., viii. 53 (1799). T. sphaero- 

 cephala Sow. Engl. Fung., t. 240 (1799). Spumaria physaroides 

 Pers. Syn. Fung., 163 (1801) ? Strongylium minus Fr. Symb. 

 Gast., 9 (1817). 



Var. minus Lister : threads of capillitium slender ; spores 

 7 to 9 [x diam. — D. humile Hazsl. in Oester. Bot. Zeitschr., 

 xxvii. 84 (1877). D. minus Morg. in Myx. Miami Valley 61, 

 1894 ; Macbr. I.e., 89. 



PI. 112. — a. sporangia (England) ; 6. capillitium and spores with fragment of 

 sporangium- wall ; c. spore ; d. sporangia of var. minus (England) ; e. capillitium 

 and spores of same ; /. spore. 



Intermediate forms uniting the var. minus and the typical form are 

 so frequent that the former cannot be regarded as a distinct species ;. 



