and "b" the difference between that percentage and 100, according to the 

 following formula: 



( axb ) 

 Pure seed tolerance=0.6+ ( 0.2x ) 



( 100 ) 



a sample of timothy guaranteed 99.20% could test as low as 98.25% 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 

 low as 77% 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 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 (ex- 

 cept 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 agri- 

 cultural 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 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 condemned if it has a 

 2.59 per cent. (2) No primary noxious weed seeds are allowed, but the 



