THEIR HABITATS GENERALLY. 19
so uncertain, that it is difficult to give more than a vague general
account of them.
Everywhere, and throughout the year, in moist weather are
to be found on dead leaves the white-stalked sporangia of
Didymium squamulosum ; and the goblet-shaped cups of
Craterium minutum are almost as common. In some
seasons Physarum sinuosum and P. bitectum, both with
compressed wavy sporangia, are conspicuous on heaps of dead
elm and bramble leaves. Bramble bushes, indeed, where piles
of both their own and other fallen leaves are held undisturbed
in a cage of spiny branches, form a favoured haunt of many
Mycetozoa. Mr. H. J. Howard describes8 his thorough method of
attacking such prickly strongholds in Norfolk woods. Armed
with stout hedger's gloves, and with a mackintosh kneeling mat,
he burrows into the centre of the bramble thicket, and there
turns over every likely-looking leaf. He has been rewarded by
discovering there large growths of Physarum carneum, a species
new to Britain and only once before found outside Colorado ;
and also quantities of the rare Physarum lateritium and Diderma
simplex, none of which he found beyond the bramble clumps.
On decaying sycamore leaves, in Wanstead Park, Didymium
anellus and Badhamia foliicola are often abundant in autumn.
Dead alder leaves mixed with bramble, in swampy copses, have
yielded the handsome orange white-stalked Physarum luteo-
album.
Beech leaves, even when lying in deep and moist layers,
seem to provide but meagre provender for plasmodium. Heaps
of decaying holly leaves afford nourishment for many Mycetozoa.
Here Didymium squamulosum is perhaps commonest, but
D. nigripes is often present in vast profusion, as also are the
charming iridescent violet and bronze sporangia of Lamproderma
scintillans, and the neat brown regiments of ' Comatricha
pulchella.
In Epping Forest, the pearl-like sporangia of Margarita
metallica have often been found on holly leaves. In a valley
near Lyme Regis, Comatricha rubens and C. lurida often abound
in winter amongst the dead leaves of the ivy which carpets the
ground. When these leaves, which often lie caked together in soft
8 See " Notes upon Physarum carneum G. Lister and Sturgis " in Journ, R. Microscop.
Soc, 1917, p. 366.