FIG, 6. OSAGE ORANGE, ILLUSTRATING ' HEARTWOOD " AND SAPWOOD 



13 



The formation of the heartwood follows very rapidly on the growth of sapwood so 

 that the latter is only a narrow layer of lighter wood next the bark. The cambium and 

 inner bark are too narrow to be defined in the photograph. Forestry Hall, Case F, 20 

 (Toxijlon pomiferym Raf.) 



