22,3 Reyes: Woods of the Philippine Dipterocarps 325 



generally flattened tangentially, with wide lumina. Vertical 

 parenchyma vasicentric, zonate or diffuse. Resin cysts com- 

 pressed, inconspicuous as compared to the vessels. Idioblasts 

 present or absent. Wood rays 3 to 9 by 35 to 90 cells in 

 transverse section. 



Remarks. — The lauaan group may be divided into two sub- 

 groups; namely, the red lauaans and the white lauaans, which 

 are separated as follows: 

 1. Wood reddish brown to brick red Bed lauaans. 



Wood pale yellow to light red or pinkish White lauaans. 



SUBGROUP RED LAUAANS 



The red lauaans are wholly confined to the genus Shorea" 

 and are characterized by the reddish brown or brick red color 

 of the wood. The following key is based on the gross and 

 minute characteristics of the wood and should assist in the 

 separation of species. 



Key to the commercial species of red lauaans. 

 1. Wood light red; resin cysts small, inconspicuous, empty, that is, without 



whitish deposits Mayapis (Shorea palosapis). 



Wood red to dark red; resin cysts conspicuous, filled with a whitish 



2. Wood soft and light, specific gravity usually less than 0.5; libriform 



fibers over 30 m in transverse diameter; organic infiltration in ray 

 parenchyma uneven and generally thin. 



Tiaong (Shorea teysmanniana) . 

 Wood medium hard and medium heavy, specific gravity over 0.5; libri- 

 form fibers less than 30 M in transverse diameter; organic infiltration 

 in ray parenchyma copious, generally indurated -- - 3. 



3. Vessels very large, averaging over 300 M in transverse diameter; tra- 



cheids three or four near the junctions of vessels; libriform fibers 

 averaging 28 by 2,020 m; specific gravity, 0.542. 



Red lauaan (Shorea negrosensis). 

 Vessels medium, averaging less than 250 m in transverse section; tra- 

 cheids absent or at most one or two proximate to vessels; libriform 

 fibers averaging 25 by 1,470 /*; specific gravity, 0.575. 



Tangile (Shorea polysperma). 



(Blanco) Merrill. Mayapis. (Plate 16.) 

 Gross features.— Sapwood light red, medium thick; heart- 

 wood darker, the color deepening with age. Wood coarse tex- 

 tured, generally cross grained, soft and light; specific gravity, 



apply. Various species 



of Shorea are included 



