292 COMMON WEEDS 



1908 ; the Transactions of the Highland and Agricultural 

 Society, 1907 ; the Bulletin of the Imperial Institute, 1903 ; 

 and the Proceedings of the Royal Society, 1903.) 



Laburnum (Cytisus Laburnum L.) is a decorative tree, 

 well known throughout the country, the drooping 

 racemes of yellow flowers appearing in May and June. 

 It is stated by Henslow to be "certainly one of the 

 most poisonous of all trees cultivated in gardens " ; 

 and Cornevin remarks that numerous experimental 

 researches have proved that the wood, bark, leaves, 

 flowers, seeds, and roots are poisonous, the seeds espe- 

 cially so. Smith includes the Laburnum among vege- 

 table irritants, producing nervous symptoms, abdominal 

 pain, vomiting, purging, and tetanic spasms. The toxic 

 principle is Cytisin. A case was recorded T by the Board 

 of Agriculture in 1908, in which two horses were alleged 

 to have been poisoned in North Wales by eating Labur- 

 num seeds, which were found in their stomachs on 

 post-mortem examination, although in very small 

 quantity. The symptoms attendant on Laburnum 

 poisoning in cattle are stated to be trembling, disincli- 

 nation to move, partial paralysis of the limbs, tympany, 

 and salivation. 



ROSACES 



The Cherry Laurel (Prunus laurocerasus L.), so com- 

 mon in shrubberies, has caused numerous accidents 

 both to man and the domestic animals on the Con- 

 tinent, and Gerlach (vide Cornevin) cited a case of the 

 poisoning of twenty-five sheep. The crushed leaves are 

 used by entomologists for killing insects. Its toxicity 

 probably depends to some extent on locality. Henslow 

 remarks that in England it appears to be much less, if 

 at all, harmful, and states that his own cows completely 



1 Jour. Bd. Agric., March 1908, p. 695. 



