Minnesota Plant Life. 



311 



in some localities as the poison-dogwood. Farther south the 

 plants reach a height of twenty to twenty five feet and are 

 small trees, but in Minnesota the poison-elder rarely exceeds 

 from eight to twelve feet. This plant is much more irritating 

 than the poison-ivy and is the cause of many of the severe cases 

 of skin-inflammation in the autumn — the season when it is most 

 virulent. 



Poison-ivy. The poison-ivy, with currant-bunch clusters of 

 gray fruit, like those of the 

 poison-elder, dififers from the 

 latter in being a low bush or 

 woody vine, in one variety 

 climbing, but bushy in another. 

 The leaves are made up of 

 three leaflets, resembling 

 somewhat the leaves of the 

 wake-robin or trillium. Poi- 

 son-ivy in fruit should not be 

 mistaken for any other Minne- 

 sota plant, but careless observ- 

 ers sometimes take for it the 

 woodbine, a member of the 

 vine family in which the leaves 

 are made up of five leaflets. 

 Both the poison-elder and the 

 poison-ivy secrete a highly 

 poisonous volatile oil which 

 rises in an invisible mist from 

 the foliage of the plant. It is 

 often not even necessary to 

 have handled the plant for 

 symptoms of poisoning to de- 

 velop. Merely approaching within a few feet of it will often 

 suffice. One can understand how this is possible by noticing 

 the distance at which he can smell the perfumes arising from 

 sweet-scented foliage or flowers, as for example, from the worm- 

 woods or the magnolias. Just as the air is permeated in the one 

 instance by the perfume, may it in the other be filled with the 

 poisonous exhalations. Among the antidotes for ivy or elder 



Fig. 152. Poison-ivy. After Chesnut. F. B. 

 86, U. -S. Dept. Ag. 



