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

 sidered and "b" the difference between that percentage and 100, ac- 

 cording to the following formula: 



( a X b ) 



Pure seed tolerance = 0.6 + ( 0.2 x ) 



( 100 ) 



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 7^ or as low as 78% and be "satisfactory." 



For weed seeds: The law requires in the labeling of agricultural 

 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 collec- 

 tively 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 mix- 

 tures 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 mixtures 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 variations 

 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 con- 

 demned 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 vari- 

 ation from the minimum requirement for labeling secondary noxious 

 weed seeds will be passed as satisfactory. 



