PLATE XXIII 



Teratoid crowngalls produced in tobacco leaves with the hop strain of Bacterium 

 tumefaciens by local (leaf) inoculations — that is, inoculation in places where shoot 

 anlage are not known to exist. 



Fig. A. — Portion of an upper leaf showing fotu- shoot-bearing tumors growing from 

 upper surface of the inoculated midrib. Leaf inoculated February i6, 1916. Pho- 

 tographed on April i. 



Fig. B . — Same as A , but the leaf reversed and the midrib stripped of its blade to 

 show two other shoot-bearing tumors which have developed from its under surface. 

 Actual height of the tallest shoot, 1.5 cm. 



Fig. C— From middle of another leaf on the same plant as A , but fiuther magnified 

 and photo made on an orthochromatic plate to show the pale green character of the 

 shoot as contrasted with the dark green of the stirrounding leaf (which is also in 

 shadow). This tumor and its shoot arise from a branch of the midrib, the latter 

 in cross section being shown at X. A smaller teratoid tumor bearing two shoots (at 

 either side of C) developed on the upper surface of the leaf and the one bearing the 

 longer shoot on its lower surface. The actual length of this shoot was 1.5 cm. The 

 leaf was curved downward and the shoot was growing out horizontally. Time, 45 days. 

 27472°— 16 4 



