The Philippine Journal of Science 1923 



The wood resembles the finer-grained yakals of the 

 genera Hoped and Balanocarpus, but differs from these largely 

 in hardness, weight, and durability. 



Gross features. — Sapwood pale white, variable in thickness; 

 heartwood pale grayish yellow turning to golden yellow or russet 

 in contrast to the yakals, which assume a much darker hue. 

 Wood very fine or fine textured, straight or rarely cross grained, 

 moderately hard to hard, moderately heavy to heavy; specific 

 gravity, 0.680 to 0.844. 



Microscopic features. — Vessels small to medium (145 to 167 ft 

 in diameter), terete or oblong in transverse section, solitary 

 or grouped ; tyloses not abundant. Tracheids and fiber tracheids 

 wanting. Libriform fibers numerous, variously arranged. Ver- 

 tical parenchyma vasicentric to diffuse-zonate. Resin cysts in 

 interrupted concentric lines, not conspicuous. Idioblasts present. 

 Wood rays narrow (not exceeding 5 cells). Organic infiltra- 

 tion variable. 



Remarks.— The manggachapui group comprises the soft, finer- 

 textured dipterocarps. They are neither so strong nor so dur- 

 able as the yakals, but are used locally as structural timbers 

 where woods of moderate strength and durability are required. 

 Not obtainable in large quantity. 



Key to the species in the manggachapui group. 



1. Pores numerous, in groups of 2 to 5; vertical parenchyma prominently 



diffuse-zonate, forming concentric bands; trees of small or medium 



size with thick sapwood Gisok-gisok (Hopea philippinensis) . 



Pores relatively few, solitary or in groups of 2 or 3; vertical parenchyma 

 prominently vasicentric or inconspicuously diffuse-zonate; trees of 

 medium or large size, with thin sapwood _ 2. 



2. Libriform fibers in distinct radial r . wanting. 



Manggachapui (Hopea acuminata). 

 Libriform fibers not radially arranged; horizontal and vertical idioblasts 



present, the latter predominating Dalingdingan (Hopea pierrei). 



HOPEA PHILIPPINENSIS Dyer. Gisok-gisok. (Plate 30, fig. 2.) 



Gross features.— Sapwood pale white, thick; heartwood pale 

 grayish yellow turning to russet upon drying, restricted owing 

 to the small size of the tree. Wood fine to medium textured, 

 straight grained, moderately hard to hard, moderately heavy to 

 heavy; specific gravity, 0.771. 



Microscopic features.— Vessels numerous, small to medium 

 sized, 80 to 191 11 (average, 145) in diameter, terete to oblong 

 or ovoid in transverse section, generally in groups of 2 to 5; 



