PIIYSARUM.] 
PIIYSARACE/K. 
59 
(B M 41G ; K. 9G) correspond with the description in his Monograph, 
but in both' of them the lime-knots, though somewhat confluenb in the 
centre of the sporangium, cannot be said to form a cyhndrical colamella, 
such as he describes. The specimen from Fries (K. 1277) taken as the 
type of this species by Massee (Mon., p. 304) is typical P. contextum in 
all the characters given by Rostafinski. The name P. Rostafinslai, 
which is given by Massee as superseding P. conglomeratum Rost., is 
unnecessary. The vitreous structure of the inner wall of the upper 
part of the sporangium is constant in all the specimens I have 
examined. Fries distinguished Dklerma conglomeratum from D. con- 
textum chiefly by the difference of the capillitium ; he describes the 
presence of a columella in both species, but speaks of the deposits of 
lime as being more largely developed in D. conglomeratum. This is 
an uncertain character, and varies in different gatherings. Rostafinski 
was the first to detect the main specific difference, and pointed out 
that in Plujsarum contextum the spores are rough and measure 10 to 13 
/i, while in P. conglomeratum they are nearly smooth and measure 
8 to 9 diam. He follows Fries in referring to a columella in P. con- 
glomeratum, but adds that it is free and not always evident, and he 
describes P. contextum as being usually without a columella. 
Hah. On dead leaves, moss, etc. — Darenth, Kent (B. M. 417) ; 
Hutton, Yorks. (L:B.M.36) j Germany (B. M. 415) ; Sikkim, India 
(B. M. 416). 
28. P. virescens Ditm., in Sturm, Deutsch. M. Pilze, vol. i., 
p. 123, PI. Ixi. (1817). Plasmodium lemon-yellow, among dead 
leaves and grass. Sporangia subglobose or irregu.larly ovoid, 
0*2 to 0*8 mm. broad, sessile, much aggregated in confluent groups, 
or gregarious, rugose or nearly smooth, pale yellowish-green, 
yellow, or olive-brown from the absence of lime ; sporangium -wall 
membranous, with dense innate clusters of minute yellow lime- 
granules, rarely without lime. Columella none. Capillitium a 
network of hyaline threads ; lime-knots fusiform, roundish or 
irregular, yellow. Spores minutely spinulose, pale violet-brown, 
6 to 9 /t diam. — Post., Mon., p. 103; Cooke, Myx. Brit., p. 13; 
Blytt, Bidr. Norg., Sop. iii. (1892), p. 4; Mass., Mon., p. 277. 
P. Ditmari Post., Mon., App., p. 8; Macbride, in Bull. Nat. Hist. 
Iowa, ii., p. 155. P. thejoteum Fr., Symb. Cast., p. 21 (1818). 
DiclymiumsinapinumQoo^Qj'M.jx.'Brit., p. 33; Mass., Mon., p. 246. 
Physarum auriscalpium Macbride (non Cooke), I.e., p. 158. 
a. genuinum: sporangia irregularly ovoid, 0-2 to 0'3 mm. broad, 
in dense clusters of 20 to 30, on a membranous hypothalhis, 
shading from pale yellow-green to orange-yellow; sporangium- wall 
with dense innate clusters of yellow lime-granules. Capillitium 
often scanty. Spores 7 to 10 /x. diam. 
/3. obscurum : sporangia subglobose, 0*4 to 0-6 mm. diameter, 
sessile, solitary, confluent, or plasmodiocarps, gregarious or 
crowded, smooth or rugose, greenish, grey, or olive-brown and 
somewhat glossy ; sporangium-wall membranous, colourless above, 
yellow at the base, without lime, or with widely scattered innate 
clusters of whitish lime-granules. Spores 6 to 8 /u, diam. 
y. nitens : sporangia subglobose, 0-5 to 0-8 mm. diam., sessile, 
gregarious, not clustered, bright yellow. Spores 7 to 9 /a diam. 
