GABRIELLE L. C. HOWARD. 61) 



4. THE ARRANGEMENT OF THE LEAVES ON 

 THE STEM. 



Besides the height and the number of leaves, the habit of 

 growth of a tobacco plant depends on the arrangement of the 

 leaves on the stem and on the inclination of the leaves, i.e., on 

 their tendency to assume an upright or a drooping position. An 

 economically profitable plant for India should possess a large 

 number of upright leaves on a stem of medium height, the 

 majorit}^ of the leaves being borne towards the base of the stem. 

 The inheritance of the height of stem and of the number of leaves 

 has been dealt with in sections 2 and 3. No definite results can 

 be given as to the position of the leaves, but in cross Type 16 x 

 Type 35, in which a form with drooping leaves was crossed with 

 one in which the leaves are upright, distinct segregation with 

 the formation of intermediates was observed. Similarly in 

 culture 694-23 (Plate XVI) the upright character of the leaves 

 of Type 51 was reproduced. 



The results concerning the mode of inheritance of the 

 arrangement of the leaves are not very complete, but some 

 interesting observations were made. With regard to this 

 character, the plants can be divided into three groups : (1) 

 those which carry all their significant leaves at the base of 

 the stem and in which the leaves consequently lie on the 

 ground ; (2) those in which the majority of the significant leaves 

 are borne near the base, the rest up the stem, and (3) those in 

 which the leaves are borne at equal intervals up the stem. 

 This latter condition, which may be termed the " ladder type," 

 is well seen in Type 51 and its offspring, No. 740 (Plate XV), 

 This particular arrangement does not depend on the number of 

 leaves or on the height of the plant. Short and tall plants alike 

 are found of this type. Type 16 is an example of a short plant, 

 with equal short internodes ; culture No. 740 of one with equal, 

 long internodes. In every case plants selected with this 

 arrangement of the leaves have bred true as regards this 



