82 THE AMEBICAN NATURALIST [Vol. LIII 



between pink-flowered varieties of N. tabacum and 

 White (S. P. I. No. 30887 from Honduras) white has be- 

 haved as a recessive. The intensity of the dominant pink 

 depends upon the pink variety used. In some crosses, 

 the blossoms of the first generation plants are similar in 

 color to the pink of the pink parent. In other crosses, 

 the pink of the first generation plants may be noticeably 

 deeper than that of the pink-flowered parent. 



A number of heterozygous plants of the first genera- 

 tion of the cross Pink (Conn. Broadleaf ) ? X Carmine ^ 

 have been used as mother plants and crossed with the re- 

 cessive white N. sylvestris, with the following results : 

 42 plants, of which 25 were carmine blossomed and 17 



pink blossomed. 

 41 plants, of which 23 were carmine blossomed and 18 



pink blossomed. 

 Here we have a total of 83 plants, of which 48 possessed 

 Carmine blossoms and 35 possessed Pink blossoms, show- 

 ing an approximation to the 1:1 ratio. In crosses in- 

 volving the species N. sylvestris, some difficulties are in- 

 volved, since the first generation plants are usually sterile 

 or nearly so. However, this sterility has been overcome 

 in the cross in which a first generation plant of the cross 

 (Pink (Conn. Broadleaf) $ X Carmine J*) was pollinated 

 with the pollen of N. sylvestris. In the second generation 

 of this cross, whites, pinks and carmines appeared. A 

 number of carmine plants were selected and their prog- 

 enies studied. One known as no. 12, proved to be homo- 

 zygous for carmine and has bred true to this color for 

 several generations. A sister plant no. 9 with carmine 

 blossoms proved to be heterozygous. In a progeny of 32 

 plants obtained from this plant, 26 were carmine and 6 

 were pink blossomed, approximating the theoretical ratio 

 3:1. 



In the cross Carmine X White, using the white-flowered 

 variety of N. tahacum S. P. I. No. 30887 from Honduras, 

 the plants produce an abundance of fertile seed. As has 

 been stated, carmine is dominant over white, but it is not 



