22,5 Reyes: Woods of the Philippine Dipterocarps 335 



yakals by the greenish cast of the wood, but little known and 

 consequently bringing a low price in the local markets. 



Hopea mindanensis is reported to be fairly common in south- 

 ern Mindanao, where it is lumbered in limited quantities; it is 

 wholly confined to that island. 



BALANOCARPUS CAGAYANENSIS Foxworthy. Narbk. (Plate 29, fig. 1.) 



Gross features.— Sapwood pale green, thick; heartwood 

 yellowish to dark green, with distinct concentric bands of grass 

 green streaks. Wood very fine textured, straight grained, hard 

 to very hard, heavy to very heavy; specific gravity, 0.833. 



Microscopic features. — Vessels numerous, small, 51 to 166 n 

 (average, 119) in diameter, terete to oval or ovoid, solitary or 

 in groups of 2 or 3; tyloses prominent. Tracheids and fiber 

 tracheids wanting. Libriform fibers numerous, small (18 to 

 1,380 fi) with walls 6.5 fi in thickness, somewhat radially 

 arranged. Vertical parenchyma prominent, vasicentric- to 

 diffuse-zonate. Resin cysts in interrupted concentric lines. 

 Horizontal and vertical idioblasts present, the latter predomi- 

 nating. Wood rays small (3 or 4 by 35 cells). 



Remarks.— Used for house posts and permanent construction 

 where strength and durability are required. Little known 

 except in the local markets of northern Luzon, where it is 

 used extensively for house posts. 



Balanocarpus cagayanensis is a tree of medium size and has 

 been reported only from Cagayan Province, Luzon. 

 HOPEA PLAGATA Vidal. Yakal. (Plate 31, fig. 2.) 



Gross features.— Sapwood pale yellow when fresh, turning to 

 dirty gray upon exposure, medium thick; heartwood pale yellow 

 to yellowish brown. Wood very fine to fine textured, fairly 

 straight grained, extremely hard and heavy; specific gravity, 

 0.99 to 1.20. 



Microscopic features.— Vessels numerous, very small to small, 

 44 to 88 /* (average, 67) in transverse section, terete to oval or 

 ovoid, in groups of 2 or 3 ; tyloses prominent, completely occlud- 

 ing the pores. Tracheids and fiber tracheids wanting. Libri- 

 form fibers numerous, small (13.6 by 1,360 /*), with walls 6.9 ^ 

 in thickness, radially arranged. Vertical parenchyma vasi- 

 centric and diffuse-zonate, the latter usually in tangential rows, 

 one cell in thickness. Resin cysts in interrupted concentric 

 lines, inconspicuous. Vertical idioblasts wanting; horizontal 



