GRASSES OF IOWA. 97 



the fact that the commercial seed of grasses and forage plants 

 contain relatively large amounts of impurities has been quite 

 generally appreciated. It is true that the quality has improved 

 considerably since that time. This is due largely to the 

 establishment and operation of numerous seed-control stations 

 and the prosecution of similar work by many of our American 

 experiment stations. Good descriptions and illustrations of 

 grasses have become more available for popular use and thus 

 a discriminative knowledge of them more widely diffused. 



A discussion of the impurities of grass seeds may be taken 

 up under two heads as follows: 



a. Intentional adulteration. 



&. Na ural or accidental impurities. 



Intentional adulteration. — The substances principally used 

 to adulterate the seeds of grasses are fine sand and the seeds 

 of cheaper and often very inferior grasses. Neither of these 

 can be detected except by a careful examination. In fact it 

 is almost impossible for the average consumer to detect the 

 , presence of a foreign grass seed in his package because the 

 seeds of some species resemble each other so closely as to 

 render it difficult for the specialist to distinguish them. R jlfs 

 reports* finding sand in some quantity in the seeds of fiorin or 

 bent grass {Agrostis alba) and sweet vernal grass {Anthoxan- 

 thum odoratum). McCarthyf states that sand and crushed 

 quartz rock have been detected in samples of timothy. 



The seed of English or perennial rye or ray grass {Lolium 

 perenne) is commonly used to adulterate the seeds of other 

 grasses, partly because it is very cheap and partly because it 

 resembles theai closely. It is frequently found in the seeds of 

 such grasses as tall fescue and meadow fescue {Festuca elatior 

 and F. elatior pi'atensis), Italian ray grass {Lolium italicum) a 

 dearer and better grass, and in orchard grass. Rolfs found 41 

 per cent of it in a pound of the Italian ray grass and 11 per 

 cent in water fescue. The amount in orchard grass is dis- 

 cussed under that species. Sheep's fescue is sometimes used 

 in seeds of crested dog's tail and is sometimes sold as red 

 fescue. Seeds of several species of worthless Poas are used 

 with the seeds of rough-stalked meadow grass {Poa trivialis) an 

 imported grass. Several other grasses are less frequently used. 



♦Preliminary report on the examination of some seeds. Bull. Iowa Agr. Exp. 

 Station 13: 75-86. 



tSeed testing: Its uses and methods. Bull. N. 0. Agr. Exp. Station. 108: 349-415. 

 1894. See 382-391. (Also Bull. 73: 73-78: 1889). 



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