60 ENDOSPORE/E. [PHTSABUM. 



Plate XXI., A.— a. sporangia, var. d, x 20 ; 5. capillitium, with fragment 

 of sporangium-wall showing calcareous discs, and spores, x 280 ; e. spore, 

 X 600 (England). 



B. — a. sporangia, var. ft x 20 ; J. capillitium and spores, x 280 (England). , 



Glycerine mountings of a. genuinum show, dispersed in the sporangium- 

 wall, flattened disc-shaped crystalline bodies with a radiating structure, 

 measuring 10 to 20 ^ diameter, such as are also found in the sporangium- 

 wall of P. psittacinum and Craterium leucocephalum. They do not 

 appear to be present in vars. /3 and y of P. virescens. Didymium, 

 terrigenum Berk. & Curt., from Carolina (B. M. 575), is given by Eost. 

 as a synonym for Physarum cinereum Rost., Men., App., p. 9. The 

 specimen is in a poor condition, but the character of the sporangia' 

 and spores and the orange-yellow lime-knots places it under P. virescens. 

 The specimen from Iowa (B. M. 1011), to which Prof. Macbride applied 

 the name P. auriscalpiuTn Cooke {I.e.), is P. virescens y nitens. 



Hah. On dead leaves, grass, etc. — a. Epping Forest, Essex (L:B.M. 

 37). j3. Lyme Regis, Dorset (L:B.M.37) ; a. France (Paris Herb.) ; 

 a. Germany (B. M. 413) ; /3. Hungary (K. 1529) ; a. Dorfhalden (B.M. 

 861). y. Maine (L:B.M.37) ; u. Massachusetts (L:B.M.37) ; y. Iowa 

 (B. M. 1011). 



29. P. insequale Peck, in Eep. N. York Mus. Nat. Hist., xxxi., 

 Bot., p. 40 (1879). Plasmodium 1 Sporangia subglobose, 0-3 to 

 0-7 mm. diam., sessile, or elongated and confluent forming plas- 

 modiocarps, gregarious, yellowisli-red, brick-red, rosy-red, or v\rhen 

 little lime is present pale bluish spotted -with red, somewhat 

 rugose, rupturing irregularly ; sporangium-wall membranous, 

 colourless above, yellow at the base, with innate clusters of red or 

 yellow lime-granules. Columella none. Capillitium a network 

 of delicate hyaline colourless or pale yellow threads, with rounded 

 lime-knots varying in shape and size, each knot with a red centre 

 surrounded by yellow round lime-granules 1 to 3 ^u, diam. Spores 

 pale violet-brown, almost smooth, 6 to 9 /* diam. — Didymium 

 lateritium Berk. & Eav., in Grev., ii. (1873), p. 65. Physarum 

 Ditmari y late/ritium Eost., Mon., App., p. 9. Didymium, croceo- 

 jiavum, Berk. & Br., in Linn. Journ., xiv. (1875), p. 84. Phy- 

 sarum, Ditmari /3 croeeoflavum Eost., Men., App., p. 9. Physarum 

 chrysotrichum Mass., Mon., p. 300 (in part). 



Plate XXII., B. — a. sporangia, x 20 ; t. capillitium with fragment of 

 sporangium-wall and spores, x 280 ; e. spore, x 600 (S. Carolina : 

 Berkeley's type of D. laterithiTii). 



Intermediate between P. rubiginosum and P. virescens ; from orange 

 forms of the latter it differs in the scattered habit of its sporangia, 

 and from both species in the curious structure of the rounded lime- 

 knots. 



Hab. On dead leaves, wood, etc. — Ceylon (B. M. 414) ; Georgia, 

 U.S.A. (B. M. 898) ; S. Carolina (B. M. 898, 899) ; Philadelphia 

 (L:B.M.38) ; Ohio (L:B.M.38). 



30. P. rubiginosum Fries, Symb. Gast., p. 21 (1817). Plas- 

 modium? Sporangia subglobose, 0'5 to 0'8 mm. diam., sessile, 

 gregarious or crowded, smooth or rather rough, orange or deep 



