THEIR HABITATS GENERALLY.
21
squamulosum has been met with repeatedly, and has even
been regarded as a distinct species.
Occasionally the dead leaves on which Mycetozoa are feeding
become submerged, but this does not necessarily injure the
plasmodium, which can live for days under water. A large
growth of Lamproderma scintillans has been seen covering the
stones exposed in a shallow stream, as well as the moss and
dead leaves along either bank ; it clearly formed one develop-
ment, and much of the parent plasmodium must have crept
over the pebbly bed of the stream under running water. Didy-
mium difforme may pass all stages of its life-cycle under water,
and has not unfrequently been found forming sporangia on
roots of hyacinth bulbs grown in water, in glass vases.9
Straw-heaps.—This habitat for Mycetozoa was, I believe,
first investigated by Mr. James Saunders, of Luton. On the
breezy chalk hills of Bedfordshire, in the good old days when
farmers were less thrifty than at present, and used to allow
piles of old straw to lie about undisturbed for months together,
many were the pilgrimages for Mycetozoa made to those heaps,
and rich were the harvests obtained. In the fragrant moist
recesses of the straw would be seen armies of the grey erect
sporangia of Physarum didermoides, along with the sessile var.
lividum ; amongst many commoner kinds here first were recog-
nised Physarum straminipes and Didymium Trochus, species
now found to be widely distributed. Sometimes Physarum
cinereum would be present in such abundance that, with any
movement of the straw, its spores arose in clouds into the air
to be dispersed by the breeze and borne away to seek their
fortunes elsewhere. The most showy species that I know of
frequenting straw heaps is Fuligo cinerea, whose smooth white
aethalia may be so abundant on straw and the surrounding
herbage that the effect is as if whitewash had been freely
sprinkled there.
Manure.--Old manure heaps are also kindly nurseries for
Fuligo cinerea and other straw-haunting Mycetozoa. On
weathered horse-dung lying exposed in pastures, we may meet
again with Didymium squamulosum. The small yellow form
of var. liceoides of Perichaena corticalis has been obtained on
9 See H. Marshall Ward. " The Morphology and Physiology of an Aquatic Myxomycete,"
Quart. Journ. Microscop. Sci., n.s., 24, pp. 64-86 (1884).