THE MEXDELIAN BEHAVIOE OF AUEEA CHAE- 

 ACTEE IN A CEOSS BETWEEN TWO 

 VAEIETIES OF NICOTIANA 

 EUSTICA 



H. A. ALLARD 



Office of Tobacco and Plant Nutrition Investigations, Bureau 

 Washington, D. C. 



IXTKODL^CTION 



The species of tobacco Nicotimia rustica comprises a 

 number of more or less distinct varieties. One of the 

 more characteristic varieties which was received from 

 Eussia (S. P. I. 85080) is a light, yellowish-green type 

 with distinctly white stems and midribs. In these re- 

 spects this type of N. rustica resembles the well-known 

 "Wliite Burley variety of N. tabacum. According to 

 Splendore/ who has described it in. detail, this white- 

 stemmed variety of N. rustica is grown commercially in 

 Eussia (Makorka,Bakoun,Kolmak,Tseco, etc.) as a pipe 

 and cigarette tobacco. In this variety of A", rustica, the 

 stems of young plants— especially if they have been 

 somewhat etiolated by crowding— are almost snow white. 

 A cross section of the stems of such plants one month 

 old reveals the fact that this whiteness is not merely su- 

 perficial, but extends entirely through the stems, whereas 

 in green varieties of N. rustica the internal structure of 

 the stems is green throughout. The cotyledons are de- 

 cidedly chlorotic and the leaves have a pale yellowish- 

 green, chlorotic appearance which becomes more marked 

 as the plants approach maturity. As a matter of con- 

 venience, the writer has applied the term "aurea" to 

 this peculiar, varietal form of chlorosis.^ 



iSplendore, A., "Due Partioolore Forme Di X. Rustica Brasilia Chwit- 

 zent e Kapa Magiara," BoU. Tech. Delia Colt. Dei Taharhi dd E. Inst. 



described by Lodewijks as having occurred suddenly in plants of V. taba- 

 234 



