PHYSARUM.] PHYSARACE^E. 55 



are seated on short white stalks. The abundant lime in the capillitium 

 and pseudo-columella are varying characters, but are unusually pro- 

 nounced in this specimen. The spores are purplish-brown, minutely 

 and closely spinulose, 9 to 10 p. diam. Prof. Macbride compares it 

 with P. fjlaucum Phill., a synonym for P. compressum, and there does 

 not appear to be any specific character by which it can be separated 

 from that species. 



Hal}. On dead wood, etc. Shrewsbury (B. M. 115) : Hitchin, Herts. 

 (L:B.M.30); Linlithgowshire (K. 1499); Germany and Poland 

 (Strassb. Herb.) ; Italy (B.M.423) ; Ceylon (B.M.419, 420) ; Australia 

 (K. 1314) ; New Zealand (K. 1282) ; 8. New Hampshire (L:B.M.30) ; 

 8. Iowa(B. M. 806); Texas (K. 1303) ; Cuba (K. 1350) ; Juan Fernandez 

 (K. 510); Paraguay (Paris Herb.) ; Nicaragua (B. M. 1010). 



22. P. diderinoides Host., Hon., p. 97, fig. 87 (1875). Plas- 

 modium 1 Total height 0'5 to 1-3 mni. Sporangia ovoid, erect, 

 stipitate or sessile, crowded, about 0-8 ram. high, 0'5 mm. broad, 

 white, or dark grey above from the falling away or discontinuance 

 of the outer calcareous crust ; sporangium-wall of three layers, 

 the outer a dense deposit of white lime-granules, deciduous, the 

 middle layer a delicate colourless membrane with scattered lime- 

 granules, closely combined with an inner purplish, hyaline, areo- 

 lated, thicker layer. Stalk variable in length and thickness, or 

 wanting, white, membranous, with innate deposits of lime-granules, 

 not containing refuse matter, rising from a plicate white hypo- 

 thallns. Columella none. Capillitium consisting of numerous 

 rounded or somewhat angular white lime -knots connected by short, 

 seldom branching, hyaline threads, which are purple at the attach- 

 ments to the sporangium-wall. Spores very dark purple-brown, 

 nearly smooth or minutely spinulose, 10 to 13 /x diam. Cooke, 

 Myx., p. 11 ; Mass., Mon., p. 291 ; Macbride, in Bull. Nat. Hist. 

 Iowa, ii., p. 154. Spumarial diderinoides Pers., Syn., Addenda, 

 p. xxix (1801). Physarum lividum (3 licheniforme Host., Mon., 

 p. 95 ; Mass., Mon., p. 304 (in part). Physarum cinereum var. 

 ovoideum Sacc., in Michelia, ii., p. 334; Sacc., SylL, vii., p. 344; 

 Mass., Mon., p. 299. 



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

 sporangium-wall and spores, x 280 ; c. spore, x 600 (Italy). 



P. cinereum var. ovoideum Sacc. on A/la/ttlnis glandulosa (B. M. 432) 

 is a short-stalked form of P. didermoides, the sporangia arising from 

 a white membranous hypothallus. P. lividum var. licheniforme Rost., 

 parts of the type of which from Schweinitz' Herb, are in the 

 Strassburg and Kew collections (K. 1249), is a sessile form of P. 

 didermoides. 



Hob. On dead wood, leaves, etc. King's Cliff, Norths. (K. 1252) ; 

 Lyons, France (B. M. 432) ; Germany (Paris Herb.) ; Italy (K. 101) ; 

 Natal (K. 8) ; Ceylon (B. M. 420) ; Iowa (B. M. 809) ; N. Carolina 

 (B. M. 998) ; Ohio (L:B.M.31). 



23. P. cinereum Pers., in Homer, N. Mag. Bot., i., p. 89 (1794). 

 Plasmoclium watery white, among dead leaves. Sporangia 

 sessile, subglobose, pulvinate, oblong or plasmodiocarps, scattered 

 or crowded, contorted and confluent, 0*3 to 0'5 mm. broad, white 

 or cinereous, more or less warted or veined; sporangium- wall 



