126
MYCETOZOA OBSERVED IN EPPING FOREST
IN THE AUTUMN OF 1912.
By Miss Gulielma Lister, F.L.S.
[At the "Fungus Forays" in October and November, Miss Lister
kindly acted as Referee for the Mycetozoa, and furnished the following
lists of the species gathered.—Ed.]
I.—Ramble between Loughton and Theydon on 19th October 1912 :—
Badhamia utricularis Berkeley : found in the plasmodium stage,
creeping on Irpex on a fallen branch, and in mature sporangia.
Physarum nutans Persoon: Several forms of this variable species were
found, viz., the typical form with nodding lenticular sporangia on slender
dark stalks ; the subspecies leucophaeum, with sporangia either sessile or
on short dark stalks ; and the remarkable var. robustum of this subspecies,
a form that occurs regularly in the autumn and winter both in Epping Forest
and Wanstead Park. It is characterized by the large sporangia having
an unusual amount of calcareous matter in the capillitium, in the stalks,
and in the hypothallus. Sometimes the stalks are as white as in Physa-
rum leucopus, but are frequently associated with others of the usual grey
or drab colour. The capillitium is more robust than usual ; there are
many flat membranous expansions at the angles of the branches, and the
time-knots are often more or less concentrated to form a central mass or
"pseudo-columella." A fine specimen of this variety was obtained by
Mr. Ross near Chingford.
Craterium munitum Fries. (syn. C. pedunculatum Trentip) : on holly
leaves.
C. leucocephalum Ditmar : on holly leaves.
Leocarpus fragilis Rost. (syn. L. vernicosus Link) : on holly leaves
twigs, grass, etc.
Didymium squamulosum Fries. (syn. D. effusum Link) : on holly leaves.
D. nigripes Fries : on holly leaves.
D. melanospermum Macbr. (syn. D. farinaceum Schrader) : on dead
twigs.
Stemonitis fusca Both : on a poplar log.
Comatricha nigra Schroeter (syn. C. obtusata Preuss) : on fallen boughs.
Trichia varia Pers. : on dead stumps of oak and hornbeam.
T. persimitis Karstin : on dead wood and leaves.
Arcyria ferruginea Sauter : on dead wood. Sporangia were found
both in the pale pink young stage, and in the deep red mature condition ;
the latter when dry became bright orange-red.
A. incarnata Persoon: on dead oak twigs.
A. denudata Sheldon (syn. A. punicea Persoon) : on hornbeam stumps.
A. cinerea Pers. (syn. A. albida Pers.): on twig;.
II. Chingford, 2nd November 1912.
The rains of the previous week, succeeding the long spell of dry weather,
had been favourable for those species of Mycetozoa whose "plasmodium,"
or creeping and feeding stage, is passed within the substance of dead wood ;
the prostrate logs, stumps, and fallen branches had probably never become
quite dry, and the recent rains had encouraged the plasmodia to feed,
and emerge into the open air to form their sporangia. But the thick