244 
FOXWORTHY. 
foliage has developed.” Kurz, 11 says, “These wood-oil trees are strictly 
no evergreens, but the succession of leaf-shedding and leaf-forming is 
here so rapid, that young leaves are already developed, while the old ones 
are still falling off.” - 
This leaf-fail seems to occur at some time during the dry season; in 
Bataan Province during the month of January and in the northern part 
of Negros Occidental in August or September. Our knowledge of mete- 
orological conditions in the Islands is so meager that we can not more 
definitely indicate the season at present. I believe the time of leaf fall 
to be near the time of flowering, but I do not know whether it may come 
a little earlier or a little later. 
Our species seem to flower and fruit annually. The flowering season 
seems to be rather short, and it takes some months for the fruit to 
mature. The fruit is usually borne in great abundance. It sprouts very 
soon after falling to the ground, sometimes even before falling from the 
tree. 
Key to the Philippine Species of Dipterocarpus. 
a. Fruit not angled, usually globose (Section Sphaerales.) 
b. Leaves small (10-13 cm long, 2-3.5 cm broad), narrow, long-caudate-acu- 
minate 8. D. sp. from Tayabas 
bb. Leaves larger, not long-caudate-acuminate, 
e. Fruit less than 2 cm in diameter. 
d. Leaves and buds hairy 7. D. vernicifluus 
dd. Leaves and buds glabrous 6. D. hasseltii 
ec. Fruit more than 2 cm in diameter. 
d. Fruit obconical or top-shaped 3. D. sp. 
dd. Fruit globose. 
e. Leaves and young shoots brown-hairy. 
f. Leaves long and narrow, membranaceous 2. D. affinis 
ff. Leaves broader, usually coriaceous 1. D. pilosus 
ee. Leaves and young shoots not brown-hairy. 
f. Secondary nerves 10-12 pairs 5. D. gracilis 
ff. Secondary nerves 16-20 pairs 4. D. trinervis 
aa. Fruit angled, with ridges or wings (Section Axati. ) 
b. Fruit very heavy and woody, with the wings reduced to thick ridges 
9. D. speciosus 
bb. Fruit with membranaceous wings. 
c. Leaves glabrous or nearly so 10. D. grandiflorus 
cc. Leaves hairy 11. D. sp. 
Section I. Sphaerales. Tube of fruiting calyx oblately or prolately 
spheroidal, without angles. 
1. Dipterocarpus pilosus Roxb. Hort. Beng. (1814) 93, nomen, FI. Ind. 
(1832) 615; Dyer in Journ. Bot. 12 (1874) 103, Hook. f. FI. Brit. Ind. 1 (1874) 
296; A. DC. Prodr. 16 2 (1868) 614; Kurz For. FI. Brit. Burma 1 (1877) 115; 
F.-Vill. Noviss. App. (1880) 20; Vidal Sinopsis Atlas (1883) xv, t. 14 f. D; 
Burck in Ann. Jard. Bot. Buitenz. 6 (1887) 199; Brandis in Journ. Linn. Soc. 
Bot. 31 (1895) 27. Plate XXXIV. 
Forest Flora of Pegu (1875) 31. 
