482 ANNUAL REPORT 



AMARANTACEAE. 



Amarantus retrojiexus, L. Pigweed. 



Common in manured soil, in fields, etc. Is is a native of trop- 

 ical America. (1) 



Amarantus albus, L. 



Common in black sandy soil. In autumn it breaks off at the 

 root and is driven before the wind. !N"aturalized from tropical 

 America. (?) 



CHENOPODIACEAE. 



Ghenopodium album, L. Pigweed. 

 Common in rich and loose soil. 

 Chenopodmni hotrys, L. Jerusalem Oak. 

 Dry soil in streets of cities. 



POLYGONACEAE. 



Eumex acetosella, L. Sheep's Sorrel. 



In gravelly soil and in old fields. It is said that where this 

 plant occurs, the soil is sour (Thaer, 15), and that an addition of 

 lime or manure will drive it away. It is certain that the soil of 

 Western Wisconsin and Soatheastern Minnesota contains a great 

 deal of lime. The absence of lime can therefore hardly account 

 for its a bundance. 



Rumex crispus, L. Curled Dock. 



More common on high land, pastures, etc. The following, 

 Rumex ohtusifolius, L. Bitter Dock, is largely found in low 

 meadows and pastures and is exceedingly troublesome in pi-e- 

 venting the growth of useful forage plants. Cattle will avoid it 

 in all conditions. It is difficult to exterminate, as it has a very 

 long tap root and is a perennial. 



Polygonum aviculare, L, Knotgrass. 



A common dooryard weed. 



Polygonum convolvulus, L. 



Common in cultivated grounds and grain fields in loamy soil. 



Polygonum erectum, L. 



Common in dooryards, etc. 



Polygonum persicaria, L. Smartweed. 



In waste places, and low grounds, rich soil. 



Polygonum hydropiper, L. Common Smartweed. 



Common in moist and wet grounds. 



