104 WEEDS OF FARM LAND 



without any post mortem, experiment, or investigation of any 

 kind. In some cases this is done purposely when the stock 

 have really died from anthrax or similar diseases. On future 

 occasions it is usually easy to find the suspected plant near 

 where the stock have been, and so reports continue to come 

 in. If the plant cannot be found, then some other plant is 

 credited with poisonous properties." 



A certain number of weeds, however, are credited with 

 causing harm the world over, and there is little doubt that 

 they are sources of definite injury when they occur to any 

 considerable extent. 



In " Plants Poisonous to Live Stock " H. C. Long l includes 

 the following farm weeds that have on occasion been found or 

 suspected to be poisonous. 



(a) Found Poisonous. Autumn crocus, bindweed, bracken, 

 buttercup, charlock, corn cockle, darnel, fool's parsley, hem- 

 lock, horsetail, persecaria, poppy, radish, ragwort, scarlet 

 pimpernel, sheep's sorrel, sorrel, spurge (various species), water 

 hemlock or cowbane. 



(ft) Suspected. Broomrape, cat's ear, dodder, ground ivy, 

 mayweed, purging flax, silverweed, sweet clover, tormentil, 

 viper's bugloss, yellow rattle. 



Although definite instances of poisoning have been recorded 

 from all the plants in list (a) comparatively few of them are 

 so virulent as to need very special precautions with regard to 

 keeping stock out of their way. The worst weeds are more 

 fully noticed in the following paragraphs : 



Bindweed (Convolvulus arvensis). This is seldom con- 

 sidered to be harmful, but the underground stems are purgative 

 and the seeds are poisonous to stock if eaten in any quantity. 2 

 If the seeds are ground up in flour they are said to render it 

 injurious to health, besides making it a bad colour. 



Buttercup (Ranunculus sp.*). Opinions differ as to the 

 harmfulness of the various species of buttercup, but many of 

 them contain an intensely acrid juice which under some con- 

 ditions, at least, may cause poisoning when the plants are eaten 

 by animals. Henslow 3 states that if too many buttercups are 

 eaten they may cause death, but that as drying dissipates the 

 deleterious principle horses and cows may then eat them with- 



1 Long, H. C. (1917), " Plants Poisonous to Live Stock," Cambridge AgrU 

 cultural Monographs, Cambridge University Press. 

 2 Ewart, A. J. (1909), loc. cit., p. 48. 

 3 Henslow, G. (1901), " Poisonous Plants in Field and Garden," p. 37, 



