PHTSAEUM.] PHYSAEACE^. 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 /it diam. Prof. Macbride compares it 

 with P. glaucum 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. 



Sab. 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. IVE. 419, 420) ; Australia 

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

 a. Iowa(B. M. 806); Texas (K. 1303) ; Cuba (K. 1350) ; Juau Fernandez 

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



22. P. didermoides Eost., Men., p. 97, fig. 87 (1875). Plas- 

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

 stipitate or sessile, crowded, abotit O'B mm. 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 Ume-granules, 

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

 thalhis. Columella none. OapilUtium 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 /a diam. — Cooke, 

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

 Iowa, ii., p. 154. Spumaria!} didermoides Pars., Syn., Addenda, 

 p. xxix (1801). Physarwni lividum P lickeniforme Host., Mon., 

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

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

 Mass., Mon., p. 299. 



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

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



P. cinereum var. ovoideum Sacc. on Ailanthus glandulosa (B. M. 432) 

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

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

 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. 



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

 Lyons, Prance (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 Pars., in Eomer,N. Mag. Bot., i., p. 89 (1794). 

 Plasmodium 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 



