326 The Philippine Journal of Science ms 



0.340 to 0.560 (average, 0.432) . Resin cysts empty in contrast 

 to the other lauaans. 



Microscopic features. — Vessels large, 117 to 367 p (average, 

 257) in diameter, rounded ovoid or oblong in transverse sec- 

 tion, diffuse; tyloses relatively abundant, thin, unlignified. 

 Tracheids very few, proximate to the vessels. Fiber tracheids 

 wanting. Libriform fibers numerous, 26 by 1,540 ft, with walls 

 averaging 2.93 y. in thickness, slightly depressed on the tangen- 

 tial side, arranged in regular radial rows. Vertical parenchyma 

 vasicentric-zonate and diffuse, abundant about the resin cyst, 

 with scanty infiltration. Resin cysts in interrupted concentric 

 rings as in Parashorea. Horizontal and vertical idioblasts 

 wanting. Wood rays narrow, 4 by 60 cells in transverse sec- 

 tion, heavily impregnated with gummy infiltration but to a less 

 extent than in S. polysperma and S. negrosensis. 



Remarks. — Mayapis is not sold at present under its own 

 name but generally as tangile or mixed with the white lauaans. 

 It is used for house construction and medium-grade furniture, 

 but requires protection from moisture, as it is one of the less 

 durable of the dipterocarps. The species is widely distributed 

 from Cagayan southward to Zamboanga, and the trees form 

 heavy stands in some localities, as in Laguna Province and 

 certain parts of Mindanao. 



Mayapis is often mistaken for almon (Shorea eximia) but 

 can be distinguished from the latter in that the resin cysts are 

 free of resinous contents in contrast to those of S. eximia. 



SHOREA TEYSMANNIANA Dyer. TlAONG. (Plate 17.) 



Gross /eafores.— Sapwood light red, distinct from the heart- 

 wood, rather thin; heartwood darker red than that of mayapis. 

 Wood coarse textured, fairly straight grained, soft and homo- 

 geneous, light; specific gravity, 0.466, easily worked. 



Microscopic features.— Vessels large, average 0.268 /* in 

 diameter, rounded in transverse section, grouped or solitary; 

 tyloses fairly common. Tracheids few, confined to the prox- 

 imity of the vessels. Fiber tracheids wanting. Libriform 

 fibers numerous, large, 31 by 1,730 * with walls that average 

 2.93 fi in thickness, arranged in regular radial rows. Vertical 

 parenchyma vasicentric-zonate, occasionally solitary and diffuse ; 

 organic infiltration variable; in the harder grades, such as those 

 coming from Sibuyan, the deposits are as thick as in Shorea 

 polysperma but much restricted and often not conspicuous in 

 the lighter grades. Resin cysts concentric as in 5. palosapis. 



