224 LISTER : THE STUDY OF MYCETOZOA IN BRITAIN. 
found several times associated with B. panicea on elm bark in 
the autumn. 
B. rubiginosa (Chev.) Rost. var. dictyospora. —Found once 
only, and then in great profusion, on a deep heap of holly leaves 
in the forest near Cook’s Folly, November 1896. 
Physarum viride (Bull.) Pers.—Not uncommon from May 
to November on old stumps and on fallen oak boughs. The 
var. aurantium , with orange sporangia, is less abundant. The 
var. incanum, with nearly white sporangia, has been obtained 
twice in the Forest ; it resembles typical P. nutans externally, 
but has yellow lime-knots. 
P. pusillum (Berk. & Curt.) Lister.—Apparently rare in 
this district. The typical form, with slender dark red stalks, 
was found in the Loughton forest in November 1896. A 
robust form, with both stalked and sessile sporangia, occurred 
on a stump in Wanstead Park in October 1904. This gathering 
resembles Badhamia panicea in so many respects that it seems 
to represent a transition stage between the two species. 
P. nutans Pers.—One of our most abundant species, occurring 
from May to January on fallen wood and stumps, rarely on 
dead leaves. The typical form, with nodding sporangia on 
slender stalks, passes into the stouter var. leucophaeum by 
gradual stages. The latter, with sporangia on short brown 
stalks or sessile, merges into var. robustum. This is a large 
form with abundant deposits of lime granules stowed away in 
the lime-knots, in the sporangium wall and sometimes in the 
stalk also. It has been abundant the last few years on fallen 
beeches at High Beach and on elm trunks in Wanstead Park. 
When the stalks are white from lime deposits, this variety bears 
a considerable resemblance to P. leucopus Link, a more slender 
species occurring on dead leaves and moss. Specimens recorded 
as P. leucopus from Bedfordshire and Hertfordshire should be 
referred to P. nutans var. robustum. 
P. compressum Alb. & Schwein.—Not common in Epping 
Forest, but found abundantly some years in summer and autumn 
in the Avenues, Leytonstone, and in Wanstead Park, on 
the bark of fallen poplars and elms. The sporangia are stalked 
or sessile, scattered or clustered, but in all forms P. compressum 
can generally be recognised even with a pocket lens by the 
very numerous rounded lime-knots of the capillitium. 
