240 Transactions British Mycological Society. 
has been cleared of jungle is already planted with this one 
species Hevea brasiliensis. The rubber plantations must there- 
fore be regarded for the present purpose as forming a more or 
less continuous forest. The ground beneath the trees is kept 
fairly clean weeded, a very different state of things from the 
natural forest with its inextricable tangle of low growing plants 
and creepers. While the trunks of the native trees usually carry 
a rich and varied epiphytic vegetation, those of the rubber 
trees are comparatively clean. There are also extensive coconut 
plantations, and here we have another case of large areas given 
up to a single species of tree. Belts of forest reserve to some 
extent interrupt the continuity of the plantations but they are 
for the most part narrow, and in the western portion of the 
peninsula rarely exceed a few miles in depth. 
When searching for Mycetozoa, rubber and coconut trees re- 
ceived special attention, partly because they were more easily 
examined, and also because they were most productive. I think 
it may be safely assumed that the Mycetozoa occurring on these 
trees have spread there from the jungle from the fact that a 
large proportion of the species which have been found on Hevea 
and coconut are also recorded on jungle timber. Hevea is a 
soft timber and yields a never-ending supply of decaying wood 
in the form of logs, stumps and boughs which are the result of 
thinning out or cutting down because of disease; they form a 
very favourable nursery for Mycetozoa. Thinned out timber, 
and diseased logs and stumps of Hevea are usually destroyed 
by burning in prepared pits (fire-pits) or are taken away and 
stacked for use as fuel; the half-burnt and stacked material has 
many times proved most productive of Mycetozoa. 
The virgin forest consists of an intimate mixture of hard, 
medium and soft wooded trees, the medium and soft woods 
probably predominating except in certain districts. Conifers are 
practically limited to a single species, the Dammar (Agathis alba 
Lam.), which occurs only sparingly. There is therefore no area 
of jungle which as regards conifers is comparable to a pine forest 
in temperate regions. The nearest approach to a natural forest 
consisting of only few species is to be found perhaps in the 
mangrove swamps. 
The hard timber usually decays extremely slowly and from 
it both fungi and Mycetozoa are usually absent or occur only 
sparingly. This apparent scarcity is probably due to the fact 
that the succession of saprophytes is spread over a much longer 
period owing to the slower rate of decay. On two hard-wood 
trees, however—Merbau (Intsia Bakeri Prain) and Rassa (Shorea 
barbata Brandis)—I have gathered small colonies of Physarum 
nucleatum and P. aurtscalpium not longer than three weeks after 
