PART I. 
POISONOUS, INJURIOUS, AND PROCLAIMED WEEDS 
(NATIVE AND INTRODUCED). 
id 
The definition of dirt by Palmerston as being matter out of its proper 
place, may also be applied to weeds. A weed is a plant out of its proper 
place, and a troublesome weed is one which makes itself objectionable by 
‘continually asserting itself in places where it is not desired, and by. 
strenuously, though passively, resisting all attempts to relegate it to its 
proper place. With the exception of a few parasitic, prickly, or burred 
plants (Rust-fungi, .Mistletoes, Star Thistle, Dodder), hardly any plants 
are absolute weeds under all conditions, and even the mistletoe by affording 
food for small birds which are of use in other ways cannot be said to be 
entirely injurious. No strongly poisonous plant again is an absolute weed, 
since the very fact that it is poisonous shows that it contains some strong 
active principle which will be of use to man when extracted. 
Thus the Deadly Nightshade yields atropin, ergot, ergotin, Strychnos, 
strychnine, &c., al] substances of great use to man. In all such cases it 
is a question of regulation and control rather than of extirpation. It is only 
when a plant has entirely gained the upper hand, or is liable to do so, that 
any question as to the slight usefulness it may possess is entirely overborne 
by the immediate need for its suppression and the danger of allowing it to 
spread further. This applies to thistles, which in times of drought when 
most pasture herbs are eaten or destroyed, and to a less extent in times 
of plenty may yield the hungry stock a certain amount of food. Neverthe- 
less, a few ricks of hay, silos, or fields of roots are worth more as a drought 
insurance than all the thistles ever grown. 
A plant may become a weed as the result of the spread of cultivation 
owing to its excessive powers of reproduction and maintenance, coupled 
with some obnoxious peculiarity. Thus the following native plants are 
included under the head of proclaimed weeds: The Mistletoe (Loranthus 
pendulus and L. celastroides), the Nut Grass (Cyperus rotundus; the 
Chinese Scrub (Cassinia arcuata) and the Prickly Acacia (Acacia armata). 
Similarly, on cleared bush, the seedlings of forest trees are weeds, although 
the adult trees in the original forest might be of great value, 
Various factors favour the abundance, increase, and spread of weeds, 
and these, although more or less inter-related, may be grouped under the 
following heads :—(1) Deforestation ; (2) pasturage methods ; (3) grass and 
forest fires; (4) drought; (5) methods of harvesting and cultivation; and 
(6) the sale and introduction of impure and infested seed. 
DEFORESTATION.—The forests of Victoria rarely attain the density of 
the pine forests.of Europe, which often cut off so much light as to insure 
the absence of all undergrowth. Instead, a more or less abundant covering 
of saplings, suckers, grasses, and shrubs grows between the trunks of 
the trees. When the latter are cut down this undergrowth grows with greatly 
