THE HAMILTON ASSOCIATION. IJ9 



NOTES ON THE GENUS RHUS. 



Read before the Hamilton Association, March s^th, i8g2. 

 BY T. J. W. BURGESS, M. B., F. R, S. C. 



The paper that I have prepared for your consideration deals 

 with a class of plants, which, whether considered with reference to 

 their beneficent or toxic effects on the human race, should be much 

 more familiar to the general public than they now are, — I refer to 

 the various species of Rhus. 



The most noteworthy example of this genus in our own country, 

 and the one to which the greater part of my remarks will apply, is 

 commonly called Poison-Ivy. When we consider how common this 

 plant is, and the number of persons liable to exposure to its noxious 

 influence — the laborer engaged in railway work and in clearing bush 

 land, the farmer working about his fences, one of its favorite habita- 

 tions, and the child so often employed in berry-picking or in gather- 

 ing the wild flowers with which our woods and meadows abound — 

 I cannot impress on you too strongly the necessity for a thorough 

 knowledge of the various species, their appearance and that of the 

 plants with which they are most likely to be confounded, their 

 poisonous effects and the prevention and cure of these. Some of 

 the varieties being used for domestic purposes, others as medicines, 

 I will also call your attention to their uses in the arts and sciences. 



The only representative of the large order, Anacardiacece, the 

 Cashew family, in northejrn North America, is this genus Rhus, a 

 name derived from the Greek verb reo, " to flow/' so called because 

 it was thought to be useful in stopping hemorrhages. Truth to tell, 

 the name was not inaptly applied by our forefathers, all the varieties 

 being possessed of more or less astringent properties, some of them 

 in a very marked degree. The genus, to the non-botanical com- 

 monly known as Sumach or Shumach, is composed of trees or 

 shrubs having a resinous or milky acrid juice ; alternate leaves ; 

 small, regular, greenish-white or yellowish flowers : and a fruit 

 formmg a sort of dry drupe. 



Not less than fourteen varieties of Rhus are or have been used 



