No. 626] GIGANTISM IN NICOTIANA TABACUM 



233 



2. Not only giant or mammotli types which breed true, 

 but intermediate or hybrid types occur spontaneously 

 which subsequently give rise to a greater or less propor- 

 tion of mammoth forms. 



3. In crosses with normal varieties the mammoth char- 

 acter is recessive, and plants invariably blossom. The 

 Fi plants average a somewhat higher leaf number than 

 the normal parent which entered into the cross. 



4. In the Fo generation mammoth plants occur in pro- 

 portions approaching the theoretical ratio of 25 per cent, 

 obtaining in a single Mendelian cross involving two con- 

 trasted unit characters. 



LITERATUBE CITED 



Beiuhart, E. G. 



1918. Uncle Sam and His Colleagues in the Connecticut Valley. To- 



es, n. K. 

 ■OS, II. K.. 



1905. Untersuchungen uud Betrachtungen iil.er d 



der Tahakspflanze. Zeitsvhrift fiir Pfla) 



No. o, pp. 257-:ai. (See page 277.) 

 Lodewijks, J. A. 



