ILLUSTRATIONS 



rpical dipterocarp forest showing 1 



Most of the trees in this type of forest are red lauaan (Shorea 

 negrosensis) , tangile (Shorea polysperma) , bagtikan (Para- 

 shorea malaanonan), and white lauaan (Pentacme contorta). 



\te 2. Parashorea malaanonan, Elements of the Wood; x 4,000 



1. A libriform or wood fiber. Note the great length, the thickness 



of the wall, and the paucity of the pits. 



2. Ray or horizontal idioblasts. Note the crystals of calcium oxalate 



and the thin membranelike wall separating them. 



3. A ray or horizontal parenchyma cell with gummy infiltration. 



4. An epithelial cell as seen in cross section. Note the simple pits 



which show its parenchymatous origin. 



5. An epithelial cell as seen in longitudinal section. 



6. A string of wood or vertical parenchyma cells. Note the large pits 



which are present whenever these cells abut tracheids or vessels. 



7. A string of wood parenchyma cells. Note the small simple pits 



which are present when these cells abut similar parenchymatous 

 cells. 



8. A vessel segment. Note the two types of pits which are present 



as in fig. 6. 



9. A string of vertical idioblasts. Note the simple pits which show 



their parenchymatous origin. 



10. A tracheid showing two kinds of pits. The large ones are pits 



leading from tracheids to parenchymatous cells, while the smaller 

 ones lead from tracheids to similar tracheids or other prosen- 

 ' chymatous cells. (See figs. 6 and 8.) 



11. A tracheid showing numerous, small, bordered pits. 



Parashorea wood, a cross section, showing relationship < 



i of the elements in 

 greater detail; X 264. 



Plate 4 



Parashorea wood, a cross section, showing prominent tyloi 



inhibit the passage of air and liquids in the ves 



Plate 5. Diagrammatic Presentation of the Formation ( 



Showing their Schizogenous Nature; x 5 



Fig. 



