22,s Reyes: Woods of the Philippine Dipterocarps 339 



tyloses sparse. Tracheids and fiber tracheids wanting. Libri- 

 form fibers numerous, small (19 by 1,320 /*), irregularly 

 arranged. Vertical parenchyma vasicentric to diffuse-zonate, 

 the latter conspicuous. Resin cysts in interrupted concentric 

 lines. Both horizontal and vertical idioblasts present, the ver- 

 tical predominating. Wood rays medium sized (4 by 70 cells) . 

 Organic infiltration inconspicuous. 



Remarks.— Used locally for posts and piling, rarely sawn into 

 lumber owing to the small size of the trees. 



Hopea philippinensis is widely distributed throughout the 

 Islands from Laguna, southern Luzon, southward to Basilan, in 

 regions where precipitation is evenly distributed throughout 

 the year. 



HOPEA ACUMINATA Merrill. MANGGACHAPUf. (Plate 30, fig. 1.) 



Gross features.— Sapwood pale white, thin, susceptible to 

 dark brown sap stain; heartwood pale grayish yellow, turning to 

 golden brown or russet upon exposure. Wood fine to medium 

 textured, fairly straight grained, moderately hard and heavy; 

 specific gravity, 0.783. 



Microscopic features.— Vessels scattered, small to medium 

 sized, 103 to 191 p. (average, 167) in diameter, rounded to ovoid 

 or oblong in transverse section. Solitary or in occasional groups 

 of 2 or 3; tyloses sparse. Tracheids and fiber tracheids want- 

 ing. Libriform fibers numerous, small (18 by 1,290 M ), with 

 walls 4 or 5 p. in thickness, in distinct radial rows. Vertical 

 parenchyma vasicentric, occasionally diffuse. Resin cysts m 

 interrupted concentric lines, not conspicuous. Horizontal idio- 

 blasts present. Vertical idioblasts wanting or inconspicuous. 

 .Wood rays small (4 by 50 cells). Organic infiltration incon- 

 spicuous. 



Remarks.— Used for bridges, medium-grade furniture, and 

 rough construction where wood of medium strength and dur- 

 ability will suffice. Manggachapui is a favorite wood for door 

 and window frames. It is one of the best-known woods for 

 shipbuilding. Less durable than the yakals. Supply limited. 



Hopea acuminata is widely distributed throughout the Archi- 

 pelago, from northern Luzon to southern Mindanao. See re- 

 marks under Anisoptera thurifera. 



HOPEA PIERREI Hance. DAUNGDINGAN. (Plate 31, fig- 1) 



Gross features.— Sapwood similar to that of manggachapui; 

 heartwood pale yellowish, turning to russet upon exposure. 



