456 GRASSES OF IOWA. 



This has been brought into the state with clover seed. It is 

 much more common in the east than in the west and is quite 

 easily recognized by its perennial habit and its long leaves, 

 which are close to the ground. The flower stalk is grooved- 

 angled from one to two feet long. It bears a cylindrical spike 

 of flowers somewhat like the common dooryard plantain but 

 much shorter. Like many of our other troublesome weeds, 

 this is native to Europe. 



Another European vagrant, the sheep sorrel, {Rumex aceto- 

 sella) is widely distributed in this state. This weed spreads 

 freely by its running root-stocks which accounts for its appear- 

 ance in mats. There is a widely prevalent opinion that ground 

 upon which it grows lacks lime. This is, however, far from 

 correct as the weed is very common in soils which contain 

 large quantities of calcareous matter. 



An ally of the above is the curled dock {Rumex crispiis). 

 This pestiferous plant is widely distributed throughout the 

 state and does much injury in meadows and pastures.* 



The best method of destroying this weed is to pull it up by 

 twisting the root and giving it a jerk. Several other species of 

 dock are common in low meadows, especially the Rumex altis- 

 simus. 



Sneeze weed {Helenium autumnale\), is a nearly smooth per- 

 ennial from two to six feet high, with yellow ray flowers. It 

 is extremely common in low grounds in many portions of the 

 state. This weed has sometimes ciused much alarm among 

 stock men, as it is said to be very poisonous. 



Prickly lettuce is another weedy member of the same order. 

 It has become very common in many parts of the state. Al- 

 though reported more than a quarter of a century ago by Dr. 

 Gray, naar Cambridge, Mass., it did not become general until 

 1885 to 1889. Prickly lettuce {Lactuca scariola), is a close kin 

 to the cultivated lettuce. It is easily recognized by its prickly 

 or bristly stem, the prickly mid-rib of the leaf, the milky 

 juice of the plant, and panicled inflorescence. The heads con- 

 tain small, yellow flowers. This plant, when growing in open 

 ground, is a compass plant, presenting two faces to the light. 

 This is due to a twist in the leaf at the base where it is attached 

 to the stem. Some years ago Dr. J. C. Arthur^ gave a full 

 account of this weed. 



*Iowa Homestead, 1898: 1. Jl. 

 + Iowa Homestead. 1893; 13 Ja. 

 + Bull. Indiana Agr. Exp. Sta. 53. 



