DESCRIPTION OF PLATE IV. 



Fig. 1. — Hicoria ovata (shagbark hickory): cross section showing very thick- 

 walled wood fibres and distinct tangential lines of wood parenchyma; large pores 



Fig. 2. — Diospyros virginiana (persimmon) : cross section showing rather in- 

 distinct tangential lines of wood parenchyma; pores without tyloses. 



Fig. 3. — Hicoria pecan (pecan hickory) : tangential section showing very 

 irregular rays, three large calcium-oxalate crystals, and numerous wood-paren- 

 chyma strands. 



Fig. 4. — Diospyros virginiana : tangential section showing fairly uniform 

 rays in storied arrangement. Crystals visible, but very small. 



Fig. 5. — The same; radial section showing vessel segments, heterogeneous 

 rays, wood-parenchyma strands, and wood fibres in storied arrangement. 



Fig. 6. — Juglans nigra (black walnut) : radial section showing rays, large 

 vessel with tyloses, wood-parenchyma strands, chambered-parenchyma cells with 

 crystals, and wood fibres. 



