1909.] PUBLIC DOCUMENT — No. 31. 31 



Common Weed Seeds in Grass Seed and 

 Cattle Foods. 



BY G. H. CHAPMAN. 



During the past two years the wi-iter has had occasion to 

 examine numerous samples of commercial feed stuffs and grass 

 seed for the purpose of identifying the various weed seeds con- 

 tained in them. The cattle feeds were examined for the De- 

 partment of Plant and Animal Chemistry, which is charged 

 with the execution of the feed law. The grass seeds tested 

 were mostly from samples sent by farmers and others. In the 

 case of the cattle feeds the seeds partly ground and partly whole 

 were added usually in the form of grain screenings, while those 

 contained in commercial grass seed are accounted for by im- 

 proper cleaning. Samples of wool waste used for fertilizer 

 purposes have been found to contain a considerable variety of 

 weed seeds, such as clotbur, bur clover, species of medicago, 

 alfalfa, rag-weed, plantain, red clover, wild turnip, corn-cockle, 

 etc. A person buying such a product should be very careful 

 to treat it with something which will destroy the germinating 

 power of the seeds before using it on the land. Treatment 

 with dilute sulfuric acid or some such reagent might be recom- 

 mended, but it is an open question as to the economy of such 

 a proceeding. 



Some of the weed seeds found in foods and seeds are harm- 

 less, but by far the greater number are noxious, and not only 

 likely to choke out useful plants and grasses, but in themselves 

 are injurious to cattle when eaten in any large quantity. These, 

 however, are easily distinguished, and a description of them 

 will be given later. A great many of the weed seeds found in 

 cattle foods are undoubtedly digested and their germinative 

 power destroyed, but some of the varieties with thick, hard cell 



