66 



WEEDS OF THE FARM AND GARDEN 



determining the scale of points: i, the recognition of the 

 seed ; 2, separation of the seed ; 3, recognition of plant ; 

 4, prevalence; 5, robbing soil ; 6, seeding capacity; 7, dis- 

 semination ; 8, vitality of seed ; 9, longevity ; 10, root and 

 stem propagation; n, obnoxious qualities; 12, forage 

 value; 13, resist eradication; 14, aggressiveness; 15, har- 

 bor fungi; 16, harbor insects; 17, soil habitat; 18, climate 

 habitat; 19 and 20, miscellaneous. Dr. Halsted gives a 

 tabulated scale showing the characters of the worst weeds 

 of the country as follows : 



For the state of Iowa the weeds given in the Iowa 

 Weed Law are the most injurious with the possible ex- 

 ception of the squirrel-tail; they are as follows: Quack 

 grass, Canada thistle, cocklebur, wild mustard, sour or 



