26 THE MYCETOZOA:
hopeless [he writes] to send sporangia on soil by post, unless
they happen to occur on sunbaked wormcasts."10 He obtained
a fine development of Physarella oblonga on such a situation.
On another occasion, Mr. Farquharson discovered the sporangia
of Perichaena depressa on dead roots some distance under-
ground.
At the present time, when the prevalence of Protozoa in soil
is found to impair greatly its nutritive value for growing crops,
the question of Mycetozoa feeding in earth has a special interest,
and more information on the subject would be welcome.
Living Fungi.—The habitat of living fungi is familiar to
us from the well-known example of Badhamia utricularis, which
feeds on the leathery fungi abounding in wet seasons on fallen
logs in Epping Forest; in other parts of Britain and elsewhere,
it appears to be far less common. Its relative, Badhamia
nitens, with bright yellow instead of iridescent grey sporangia,
also feeds on leathery fungi, but far less exclusively. Another
species, which may possibly obtain its food from living fungi,
is Trichamphora pezizoidea ; the conspicuous saucer-shaped
sporangia, balanced on long stalks, have been found repeatedly
on the gelatinous lobes of Auricularia mesenterica growing from
old willows, but whether the fungus or dead wood has been the
host is not clear. Trichamphora is an abundiant species in the
tropics and has been obtained several times in Europe. There
seems no reason why it may not be met with in the, British Isles
also.
Living Lichens.—On this habitat occurs Hymenobolus para-
siticus, a curious species differing from the true Mycetozoa in that
the spores give rise to amoeboid bodies, which unite to form
plasmodia without passing through a flagellate stage ; the
plasmodium also does not exhibit the characteristic rhythmic
circulation, but only sluggish irregular internal movements
and, instead of spreading in a network of veins, it slowly burrows
into the lichen thallus, on the living hyphae of which it feeds :
when abundant, the plasmodia can just be detected with the
naked eye as rosy specks scattered over the surface of various
species of Parmelia, and there they form sporangia. That
they can be more active was noted by Mr. Cran, who found
10 "Notes on South Nigerian Mycetozoa," by C. O. Farquharson and G. Lister,
Journal of Botany, liv., 123.