THE AUSTRALIAN NATURALIST. 75. 
entrance to the twigs of the apple or pear through wounds or 
through the flowers. They are easily carried by insects to the. 
stigma of the flower and from this! point work. their way into 
the twig which, when infected, is eventually killed by the. 
parasite. The leaves turn brown, as if scorched by fire, hence: 
the name ‘‘Fire Blight.”’ 
Several species of Bacteria are very useful, as for example. 
those found in the nodules of Leguminous plants and which. 
assist in the manufacture of albumenoid substances. 
Myxomyceres (Slime Fungi).—This is considered an inde- 
pendent group of organisms holding an intermediate position 
between plants and animals, and have in consequence been 
termed Mycetozoa or Fungus animals. It is an interesting 
group and contains a number of species of various shades of 
colour as white, yellow, red, brown, blackish and sometimes 
_ashy-grey. They are mostly visible to the naked eye and are 
usually found in very damp places on rotten logs or timber. 
They are commonly known as slime-fungi, on account of the 
way in which the spore-walls break up, and the protoplasmic 
contents form a naked mass somewhatlike a thick yellowish or 
‘milky fluid which is known as the plasmodium. This mass of 
plasmodium creeps about and lives on decaying matter and 
finally becomes dryer in character and draws itself up into a 
definite shape which is then known as the fruiting stage. 
One of the commonest species of this group around Sydney 
is Stemonites fusca. It is. simply wonderful in structure, as 
it is composed of a central column around which is formed 
a beautiful delicate net-work, known as the capillitium in 
the meshes of which are contained countless millions of 
brownish-coloured spores. 
DisrasEs IN Pianrs Causep py Fune1.—The Rusts and 
Smuts are well-known to many of our farmers throughout 
the State on account of the enormous damage caused by these 
minute parasites. At the Inter-Colonial Wheat Conferences 
held in 1890-1896, a great deal of discussion took place on the 
rusts in our wheat and other cereal crops, but so far no 
successful remedies have been found to eradicate them, and 
the only means of growing clean crops is by securing immune 
varieties on the lines suggested by the late Mr. Farrer. 
In addition to the rusts found on cereals, we have a great 
number of species of the genus Puccinia, which infest many 
of our cultivated plants in Sydney and suburbs, as well as 
native wild plants within easy reach of the metropolis. Sun- 
flowers, Marigolds, Daisies, Hollyhocks, are all subject to in- 
fection. Several species of smut are also common on grasses 
around Sydney. 
J 
