332 The Philippine Journal of Science 1923 



Shorea eximia is reported from the eastern part of Luzon 

 southward to Zamboanga, but like Parashorea is confined to 

 regions where a dry season is not pronounced. 

 PENTACME MINDANENSIS Foxworthy. Mindanao white lauaan. 

 (Plate 24.) 



Gross features. — Sapwood whitish, turning pale gray in dry- 

 ing; medium thick; heartwood pale grayish to grayish brown. 

 Wood coarse to very coarse textured, cross grained, soft to 

 moderately hard, light to moderately heavy; specific gravity, 

 0.555. The wood is practically identical with white lauaan 

 except for its coarser texture. 



Microscopic features.— Vessels large to very large, 117 to 

 412 (x (average, 320) in diameter, oblong in transverse section, 

 solitary or in groups of 2 or 3 ; tyloses sparse. Tracheids 1 to 

 6, relatively inconspicuous. Fiber tracheids wanting. Libri- 

 form fibers numerous, large (25 by 1,910 /*), radially arranged 

 in distinct rows. Vertical parenchyma vasicentric and diffuse, 

 the latter occasionally zonate. Resin cysts in interrupted con- 

 centric lines. Horizontal and vertical idioblasts present. Wood 

 rays broad and relatively high, 6 or 7 by 60 cells. 



Remarks. — Used for the same purposes as white lauaan and 

 bagtikan, and in all probability identical in durability. The 

 wood of the species is sold as white lauaan, from which it is 

 distinguished only with difficulty. 



Pentacme mindanensis is confined wholly to Mindanao, where 

 it occurs in admixture with other dipterocarps. 



PENTACME CONTORTA (Vidal) Merrill and Rolfe. White LAUAAN. 

 (Plate 25.) 



Gross features.— Similar to those of Mindanao white lauaan 

 except for the slightly finer texture and lighter weight; specific 

 gravity, 0.471. 



Microscopic features.— -Vessels medium to large, 103 to 279 ^ 

 (average, 219) in diameter, terete or oblong in transverse sec- 

 tion, solitary or in groups of 2 to 4; tyloses sparse. Tracheids 

 few, 1 to 6, inconspicuous. Fiber tracheids wanting. Libri- 

 form fibers numerous, large (28 by 1,450 /*), in distinct radial 

 rows, simulating the tracheids of coniferous wood; lumina 

 broad. Vertical parenchyma vasicentric and diffuse; incon- 

 spicuous and difficult to identify in transverse section from the 

 thin-walled libriform fibers. Resin cysts in interrupted con- 

 centric lines, inconspicuous. Horizontal and vertical idioblasts 

 present. Wood rays varying directly according to density. 



