LISTER : THE STUDY OF MYCETOZOA IN BRITAIN. 225 
P. cinereum Pers.—Fairly common on dead leaves in autumn. 
P. vernum Somm.—The typical robust form has not been 
recorded from Essex ; the var. iridescens Lister, a small form 
with globose or vermiform iridescent sporangia, is usually 
abundant on dead holly leaves in autumn ; this variety is 
nearly related to P. cinereum . from which it differs in its larger 
lime-knots and dark spores. 
P. sinuosum (Bull.) Weinm.—Frequent on twigs, and on 
dead elm and bramble leaves, in autumn and winter, especially 
in Wanstead Park ; the white plate-like or frilled plasmodiocarps 
form conspicuous objects on the dark leaves. 
P. bitectum Lister.—Frequent, and often found associated 
with the preceding, which it closely resembles. P. bitectum 
can usually be distinguished in the held by the outer layer 
of the sporangium-wall peeling back from the inner layer 
and by the much larger lime-knots. 
P. virescens Ditm.—Not common, appearing in summer 
on moss and grass ; unless observed in the bright yellow plas- 
modium stage, this species with its small greenish-grey clusters 
of sporangia may be easily overlooked. The var. obscurum 
Lister occurs on dead holly leaves in autumn and winter ; it 
has been observed several times in the forest. 
Fuligo septica (L.) Gmel.—Very abundant on dead wood 
throughout the summer and early autumn. The aethalia are 
usually yellow, sometimes white or brick-red. 
F. muscorum Alb. & Schw.—Apparently not common. 
It appeared in great abundance developing from apricot-coloured 
plasmodium on heather and living holly sprays, in September 
and October 1909, and again in October 1916 near They don. 
The mature aethalia are very easily overlooked, having the 
appearance of small lumps of yellowish-grey clay. 
F. cinerea (Schw.) Morgan var. ecorticata Lister.—This 
has once only been recorded from Essex : a group 01 pale grey 
aethalia were found developing from white plasmodium on 
bracken and dead leaves in the forest at Theydon, October 1909. 
Craterium minutum (Leers) Fries.—Common on dead leaves 
from summer to spring, most abundant in autumn. 
C. leucocephalum Ditmar.—Not unfrequent from July to 
November amongst dead leaves. 
C. aureum (Schum.) Rost.—One gathering of this beautifu 1 
