Xo. 02(3] GICAXTISM L\ XICOTIAXA TAB ALUM 225 



expected ratio 1820/4:= 455, if the Mammoth habit be- 

 haved as a simple Mendelian character in contrast with 

 the normal blossoming habit. 



From these data it would appear that the Mammoth 

 character is recessive in its inheritance and reappears in 

 the Fo generation in numbers approximating closely the 

 expected ratio for a simple Mendelian recessive. 



The Origin and Behavior of a New Mammoth Type of 

 Tobacco ix a Lixe Descexdix^g from a Species Hybrid 

 In an earlier paragraph it has been mentioned that the 

 Maryland Narrowdeaf Mammoth and a Burley Mammoth 

 appeared in the generation of certain crosses. In the 

 writer's experience a giant type appeared in third gen- 

 eration plants descending from a species cross. 



In 1914 the blossoms of a first generation plant of the 

 cross Connecticut Broadleaf (pink) ? X Giant Bed flow- 

 ering (carmine) were pollinated with the pollen of 

 Nicotiana sijlvestris ( white). ^ Although first generation 

 plants of crosses between the species N. tabacum and N. 

 sylvestris are likely to be sterile, or nearly so, consider- 

 able fertile seed were obtained from Fi generation of this 

 particular cross. In the second generation there was a 

 noticeable segregation into plants with pink, white and 

 carmine l)lossonis. The size and shape of the blossoms 

 of tlic plants (if the Fo generation were also very variable 

 and A aridiis ahiionnalities were noted. Some plants were 

 completely self-sterile and others produced blossoms with 

 supenuiiiu'rai-y ))etals. A number of plants producing the 

 largest and finest earmine-colored V)lossoms were selected 

 for further inheritance studies. Tlie progenies of two of 

 these mother plants, nos. 9 and 12, were grown in the field 

 at Arlington, Va., during the season of 191 (i. 



The mother plant, no. 9. proved to be heterozygous, 

 breaking up into carmiiu's and pinks, approximating the 

 theoretical ratio of three carmines to one pink. All the 

 plants of tliis line were normal in size and habit of growth. 



• 3 The so-called Giant Ee.I flowerincr tobacco sold bv seedsmen for orna- 

 mental purposes, is only a variety of A', iahacum with deep carmine blossoms. 



