106 MANUAL OF POISONOUS PLANTS 



Urticaceae. 



Madura pomifera (Raf.) Schneider. Osage orange. 



Cultivated especially in the southern part of Iowa to Nebraska and South- 

 ward. The leaves and fruit are more or less poisonous. The thorns upon the 

 plant produce serious injuries giving rise to inflammation. 



Humulus Lupulus L. Common Hop. 



Hop pickers often have an inflammation of the hands. The plant is a 

 sedative and contains cholin, lupulic acid and oil of humulus, 



Cannabis sativa L,. Hemp. 



Naturalized in many parts of the North. The narcotic effect of the resin 

 of the plant is well known and in India an intoxicating drink is made from the 

 juice of the leaves. Contains the substances cannabin, and oxycannabin. 



Urtica dioica L. Stinging nettle. 



The urticating properties of out common nettle are known to all who have 

 had any experience in collecting the plants; there is at first a reddening, fol- 

 lowed by a swelling, intense burning, and a small amount of itching. It is 

 said to contain formic acid. The Western Nettle U. holoserkea of Utah has 

 similar properties. 



Urtica gracilis L. Slender nettle. 



Injurious like the preceding but more widely distributed. 



Laportea canadensis Gaud. Wood nettle. 



This plant is even more widely distributed than the preceding nettles. It 

 is found in deep woods. It produces an irritation of the skin like that caused by 

 common nettle. 



Loranthaeeae. 



Poisoning has been reported from the European mistletoe Viscum album 

 and there are a few references in America regarding poisoning by the false 

 mistletoe Phoradendron flavescens. Possibly the Arceuthobiums may also be 

 injurious. 



Aristolochiceae. 



Artistolochia Clematitis L. 



Atlantic States from New York to Md. Some of the European species 

 of Aristolochia are poisonous like the A. Clematitis which is naturalized along 

 the Atlantic Coast. 



Polygonaceae. 



Rumex acetosella L. Sheep sorrel. 



The plant is widely distributed in the U. S. and is becoming more common. 

 Said to be poisonous to horses and sheep. Contains oxalic acid. 



Rumex crispus L. Sour dock. 



The plant is an astringent and is looked on with suspicion as are some of 

 the other species of the genus. 



Fagopyrum esculentum Moench. Buckwheat. 



A dermatitis produced by the eating of buckwheat cakes is well known to 

 most people and occasionally where screenings of this material are fed in 

 quantities to hogs a similar rash is produced. Buckwheat straw is also con- 

 sidered poisonous. The plant contains the glycoside indican. 



Fagopyrum tataricum Gaertn. 



Poisonous like the preceding. 



Polygonum acre H B K. Smartweed. 



