This is the ratio of the length to breadth of the leaf blade (or leaflet blade in the case of compound leaves) not including the stalk. For example a leaf blade 7 cm long and 7 cm wide would have a length/breadth ratio of 1 and would be included in feature L14. A leaf blade 5 cm long and 1 cm wide would have a ratio of 5 and would be included in feature L16.
A method of calculating this is to divide the length by the width:
a. Length 7 cm divided by width 7 cm = 1. Also 7/7 = 1.
b. Length 5 cm divided by width 1 cm = 5. Also 5/1 = 5.
c. Length 5 cm divided by width 2 cm = 2.5. Also 5/2.5 = 2.