CHAPTER VII. 



POISONOUS AND INJURIOUS WEEDS. 



THE most obvious damage done by weeds is that to the crops 

 among which they grow, but a certain number of plants work 

 harm by poisoning or otherwise injuring live stock or human 

 beings or by affecting various farm products, for instance milk 

 and wool, in such a way as to depreciate their market value, 

 so causing waste and loss. In some cases it is probable that 

 damage from this cause has been over-estimated, but there' is 

 no doubt that it is a point that needs to be borne in mind and 

 guarded against as far as possible. The plants concerned 

 may be considered under two headings : 



(A) Weeds that are harmful to live stock and human 

 beings. 



(B) Weeds that injuriously affect farm products. 



The majority of these are plants possessing some poisonous 

 qualities which either cause death to the animals eating them 

 or else make the stock ill and put them out of condition, 

 financial loss resulting in either case. Exact knowledge on 

 this subject is very difficult to obtain. The reports on sus- 

 pected plants from various sources are often conflicting, and 

 in most cases hardly anything is known of the true action of 

 the weeds concerned. Also, it is occasionally to the benefit of 

 the unscrupulous to attribute the death of stock to a poisonous 

 weed rather than to its true cause. Ewart l sums up the 

 state of affairs as follows : " It is exceedingly difficult or 

 impossible to draw a definite line of demarcation between 

 poisonous and non-poisonous plants. The usual origin of the 

 report as to the poisonous character of a plant is that some 

 stock die, and the nearest plant is selected as the scapegoat, 



1 Ewart, A. J. (1909), " The Weeds, Poison Plants, and Naturalised Aliens 

 of Victoria," p. n. 



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