No. 626] GIGANTISM LV A7r 077.4 .V.I TABACUM 



221 



Mammoth characteristics from generation to generation. 

 Intermediate forms have not been observed. 



Behavior of Gigaxtism in" Crosses 

 Since Mammoth forms are now grown connnercially in 

 the United States and ])romise to become vahiable new 

 varieties, it has been considered desirable to determine 

 the ])ossibility of combining the Mannnoth character of 

 indeterminate growth or gigantism with other characters 

 of commercial vahie by crossing Mannnoth types with 



'V\\v Mai'\ land XaiTowlcat' .Mannnoth has been crossed 

 with a number of pin'c lines ol' the more distinct varieties 

 nf XicnlhiiKi IdbacioH, including White Burley, Yellow 

 I'r.Nor. Little Oronoco, C^onnecticut Broadleaf, and the 

 vei'\ (li-tinct variety known as A^. Clnnensis (S. P. I., No. 

 4L'.:!,"3r)). In all these crosses the Mannnotli characteristic 

 l)ehaves as a unit character and is rccessiNc to normal 

 size and normal blossoming hal)it ol' ilie oi'dinary 



A Maryland AFannnoth and a liurlcy Maiumnth. x'cui-ed 

 as the rcMilt nf \hc rm-^. Mai'> land .\iaiiiiMoili ^ Wliiti- 

 Burley o, hav(> aUo hrcn (tos.mmI with the distinct s]Rvit-. 

 A", mz/^-./ms aihl .V. ah<rni"^n. In llu-e rr..^M- ihr V 

 planN invariablx liav.^ iM.^^onied nnrniallx a^ ^^hr^v 

 rVn.^r^ Iliad. ■ wilh varirti(- nf .V. fnluiun,.. 



of all .Mammoth cio^m'. haxv l.i..^^nnHMl ir prac-t'irall> 



a; tnhacuL The plants, however, are UMiall> M.niewhat 

 taller and. on an averauv, produce a mmucw hat hi-lier leal 

 number than the ordinarv \ ai'ieti<-s. >liowing that the F. 

 plants aro nioiv Ir^. interiiUMliate hctueen the normal 

 atui the Mairmi..ih parents. Tlii^ relation of leaf number 

 is shown ill M\-ihle 1. 



Ii; r, brtuorn Liltlo Dutch a, id Marxlaud Maii^ 



