54 WEEDS OF THE FARM AND GARDEN 



The blue vervain (Verbena stricta), with hairy leaves 

 and long spikes of blue flowers, is common in many pas- 

 tures of the northern Mississippi valley. Yarrow is also 

 common, not only in northern states, but across the con- 

 tinent, especially in dry pastures and meadows. 



Two weeds of the morning glory family are very fre- 

 quently found in Iowa. One, the European bindweed 

 (Convolvulus arvensis), has made its way from Illinois 

 and Missouri, where it is already something of a pest, and 

 is now seen in meadows in Iowa. The other, the com- 

 mon morning glory (C. sepium), very closely allied to the 

 above, is common in low meadows, where it has long 

 been known as a persistent, troublesome weed. It differs 

 from the European bindweed in having much larger 

 flowers' and longer twining stems. It not only shuts out 

 the light from the grass, but its presence in hay renders 

 the latter less valuable. There is no method of exter- 

 minating this weed except by close pasturing and prefer- 

 ably using the pasture for hogs. It must be taken up root 

 and all or it will not be subdued. 



Milkweed (Asclepias syriaca) is frequently troublesome 

 in meadows of the north; the showy milkweed from 

 Iowa to Utah and the swamp milkweed (A. incarnata) 

 are also seen in low meadows of the North. 



Horse nettle (Solanum caroUnense) is also frequently 

 complained of. Allied to this is the buffalo bur (S. ros- 

 tratum), a bushy annual which grows only in open places 

 in the meadow and would not occur if the meadow were 

 kept in good condition. It is common in the Rocky 

 Mountain country and from Kansas to Texas. 



Cowbane (Cicuta metadata), belonging to the same fam- 

 ily as the carrot, parsnip and celery, is a frequent inhabi- 

 tant of low meadows in Iowa and is easily recognized by 

 its white flowers borne in umbels. It is one of the most 

 deadly poisonous plants of the North, the poison resid- 

 ing in the root. Many cases of poisoning of human 



