For purity: Allowing "a" to represent the component being 

 considered and "b" the difference between that percentage and 100, 

 according to the following formula : 



Pure seed tolerance = 0.6 + ( 0.2 X a * ) 



a sample of timothy guaranteed 99.20 would have an allowable vari- 

 ation of .75 or could test as high as 99.95 or as low as 98.45 and be 

 "satisfactory." 



For germination : The following tolerances are applicable : 



Healthy sprouts found by test in each 100 seeds Tolerance 



96 or over 5 



90 or over but less than 96 6 



80 or over but less than 90 7 



70 or over but less than 80 8 



60 or over but less than 70 9 



Less than 60 10 



Therefore, a sample of seed guaranteed 85% for germination may 

 be as high as 92% or as low as 78% and be "satisfactory." 



For weed seeds: The law required in the labeling of agri- 

 cultural seed (1) that the percentage of all weed seeds present shall 

 be shown on the tag, (2) that no primary noxious weed seeds shall 

 be present in the sample, and (3) that secondary noxious weed seeds 

 shall be given by name and approximate number, per ounce in groups 

 (A) and (B) and per pound in groups (C) and (D), when present 

 singly or collectively in excess of — 



(A) one seed or bulblet in each 5 grams of Agrostis species, 

 Poa species, Rhodes grass, Bermuda grass, timothy, orchard grass, 

 fescues (except meadow fescue), alsike and white clover, reed canary 

 grass, Dallis grass, and other agricultural seeds of similar size and 

 weight, or mixtures within this group ; 



(B) One seed or bulblet in each 10 grams of ryegrass, meadow 

 fescue, foxtail millet, alfalfa, red clover, sweetclovers, lespedezas, 

 smooth brome, crimson clover, Brassica species, flax, Agropyron species, 

 and other agricultural seeds of similar size and weight, or mixtures 

 within this group, or of this group with (a) ; 



(C) One seed or bulblet in each 25 grams of proso, Sudan 

 grass and other agricultural seeds of similar size and weight, or mix- 

 tures not specified in (A), (B), or (D) ; 



(D) One seed or bulblet in each 100 grams of wheat, oats, 

 rye, barley, buckwheat, sorghum (except Sudan grass), vetches, and 

 other agricultural seeds of a size and weight similar to or greater than 

 those within this group, or any mixtures within this group. 



Certain tolerances are allowed, however, to provide for vari- 

 ations and unavoidable errors, but only within very narrow limits 

 and for which there is always a standard formula for computation. 

 Examples: (1) Timothy guaranteed only 2 per cent weed seeds will 

 not be condemned if it has a 2.59 per cent. (2) No primary noxious 

 weed seeds are allowed, but the presence of two such seeds in 50 

 grams of timothy would not be considered a violation. (3) Similarly, 

 some slight variation from the minimum reauirement for labeling sec- 

 ondary noxious weed seeds will be passed as satisfactory. 



