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THE AMERICAN NATURALIST [Vol.XLVIII 



of wrapper tobacco, but the crop when cured lacked uni- 

 formity. Some leaves of exceptionally high quality were 

 produced, but the crop in general lacked that characteris- 

 tic known as " grain" and had too large a proportion of 

 heavy leaves — the so-called "tops." 



From this 1908 generation 100 seed plants were selfed, 

 their leaves harvested, cured and fermented separately, 

 and data on quality recorded. The type was also grown 

 commercially on a large scale. The commercial results, 

 however, have been reported in another paper. "We are to 

 consider only the results of the selection experiment that 

 began in 1908, through the cooperation between the U. S. 

 Department of Agriculture and the Connecticut Agricul- 

 tural Experiment Station, a joining of forces that in 1909 

 included the Bussey Institution of Harvard University. 

 Shamel ( :07) considered the strain produced by this cross 

 to be the result of a mutation. From a study of the 

 data from the previous work on the cross it seemed to the 

 writers that a different interpretation of the results might 

 be made. While it was not impossible that the many- 

 leaved type that had been isolated was the result of a 

 mutation, it appeared much more probable that it had 

 arisen through a recombination of Mendelian factors. 

 The type had the habit of growth and size of leaf of the 

 pure "Havana" variety and the number of leaves of the 

 "Sumatra" variety, a combination that might reason- 

 ably be expected to be the result of the Mendelian law. 



Besults on the Keciprocal Cross, "Sumatra" 

 X "Havana" 

 To test the hypothesis that the new tobacco was the 

 result of such recombination and could be reproduced 

 whenever desired, the reciprocal of the original cross was 

 made in 1910. The female parent, "Sumatra," was the 

 direct descendant of a sister of the plant used as the 

 male parent of the original cross by Shamel in 1903 

 through seven generations of selfed plants. The male 

 parent, "Havana," was from the commercial field of the 

 Windsor Tobacco Growers' Corporation at Bloomfield, 



