PHYSARUM.] PIIYSARACIE/E. 03 
e. I.imo-knots white, sporangium grey or white- 
Stalk straw-coloured, capillitium with a central ball 
of lime. 17. P. nudeatum 
Stalk buff, black, or white; sporangium subglobose ; 
spores bright violet-brown. 19. F. nutans 
Stalk black, buff, or white; sporangium laterally 
compressed ; spores dark purple-brown. 
21. P. comioressum 
Stalk red-brown, sporangium globose, white. 
20. P. calidris 
Stalk white, membranous, sporangium ovoid. 
22. P. didermoides 
B. Sporangia sessile (never stalked) : — 
A. Lime-knots white — 
a. Sporangium -wall single, spores pale violet-brown. 
23. P. cinereum 
b. Sporangiiim-wall double — 
a Sporangia scattered — 
Sporangia sinuous, muriform, inner wall fragile. 
24. P. bivalve 
Sporangia subglobose, or plasmodiocarps, inner 
wall persistent. 25. P. Didemia 
ft Sporangia crowded — - 
Sporangia renrform or subglobose, spores dark, 
rough, 10 to 14 fx,. 26. P. contextum 
Sporangia angled by mutual pressure, spores pale, 
nearly smooth, 8 to 10 /X. 27. P. conglomeratum 
B. Lime-knots red, or yellow — 
Lime-knots yellow, small, angular. 28. P. virescens 
Lime-knots red, large, angular. 30. P. rubiginosuni 
Lime-kuots yellow with red centre, rounded. 
29, P. incequale 
1. P. leucopus Link, Diss. I., p. 27 (1809). Plasmodium 
opaque white. Total height about 1 mm. Sporangia globose, 
cinereous, or glaucous, 0*5 mm. diam., gregarious, stipitate ; 
sporangium-wall delicately membrauous, containing scattered or 
clustered, white, globular lime-granules. Stalk white, stout, 
0"15 to 0*2 mm. thick, with a few shallow longitudinal furrows, 
erect, rigid, brittle, somewhat narrowing upwards, chalk-white 
in section to the base, rising from a more or less developed white 
hypothallus ; enclosing no refuse matter. Columella none, or 
scarcely evident. Capillitium white, consisting of delicate, 
branching, hyaline threads connecting the large irregular knots, 
