22,8 Reyes: Woods of the Philippine Dipterocarps 329 



Madison, Wisconsin, tangile is approximately 14 per cent greater 

 in weight or density than true mahogany. It was also found 

 that the "mechanical properties of tangile compare favorably 

 with those of true mahogany." Not durable when exposed to 

 the weather or in contact with the ground. Tangile is known 

 by several trade names outside the Islands such as "Philippine 

 mahogany," "tangile mahogany," and "Bataan" or "Bataan 

 mahogany." 



Shorea polysperma is one of the most abundant of the red 

 lauaans. It occurs from Cagayan southward to Cotabato and 

 is cut in large quantities. 



SUBGROUP WHITE LAUAANS 



The white lauaans, as the term implies, are characterized by 

 pale yellow to light red or pinkish wood, and include the species 

 of Parashorea and Pentacme, and light-colored Shorea species 

 that occur in the Islands. They are the most abundant of the 

 dipterocarps and are found throughout the Archipelago wherever 

 this type of forest occurs. The distinguishing characteristics 

 of the wood of the most-important members are given in the 

 following key: 



Key to the genera and species of white lauaans. 



1. Wood pale yellow; pores medium, average 200 MJ horizontal and vertical 



resin cysts present; vertical idioblasts wanting. 



Kalunti (Shorea mindanensis). 



Wood not of yellowish cast; pores medium to very coarse, generally 



average over 200 m; horizontal resin cysts wanting; vertical idioblasts 



2. Wood grayish or brownish, medium hard to hard, moderately heavy; 



average specific gravity, 0.593; tracheids prominent, 2 to 12 in number. 

 Bagtlkan (Parashorea malaanonan). 

 Wood grayish white to light red or pinkish, soft to medium hard, light 

 to moderately heavy; specific gravity rarely over 0.55; tracheids in- 

 conspicuous, 1 to 6 in number 3. 



3. Wood light red to pinkish or often with vinaceous tinge; pores numerous, 



predominately oblong; idioblasts wanting or very sparse. 



Almon (Shorea eximia). 

 Wood grayish white; pores relatively few; vertical and horizontal idio- 

 blasts numerous 4. 



4. Wood coarse to very coarse textured; pores large, average over 300 p- 



in diameter; average specific gravity, 0.555; libriform fibers narrow, 



25 by 1,910 /i Mindanao white lauaan (Pentacme mindanensis). 



Wood medium to coarse textured; pores medium to large, average less 

 than 300 /* in diameter; average specific gravity, 0.471; libriform fibers 

 broad, 28 by 1,450 n White lauaan (Pentacme contorta). 



