OF THE DIPTEROCARPACEX. 7 
many years under dense cover of tall grass, of bushes, or other 
trees. It will be understood that these remarks relate to Sal 
forests in their natural state. Where man interferes by cutting 
out the Sal tree, because it is the most valuable timber, the 
forest of course assumes a different aspect. 
Another species remarkable for its gregarious habits is the 
Eng tree of Burma, Dipterocarpus tuberculatus, Roxb., forming 
extensive forests, chiefly on laterite, at the foot of the hills 
in Pegu and Upper Burma. As in the case of Sal, there is 
under the parent trees an abundance of younger trees of the 
same kind, of all ages down to seedlings. The same peculiarities 
which were noticed in the case of the Sal tree also favour the 
growth of the Eng and give it, under suitable conditions of soil 
and climate, preponderance over its associates. 
The following is a list of the principal species known to grow 
gregariously :— 
1. Dipterocarpus obtusifolius, Teysm.—Eastern peninsula 
south of 20? N. lat. In Burma this takes the place of D. 
tuberculatus at higher levels. 
2. D. pilosus, Roxb. (D. Baudii, Korth.).—Gregarious in 
Sumatra (Korthals), not gregarious in Burma. 
3. D. Duperreanus, Pierre, and (4) Jourdainii, Pierre.— 
Cochinchina, gregarious (Pierre). 
5. D. tuberculatus, Roxb.—Eminently gregarious on laterite 
in Burma. 
6. D. intricatus, Dyer.—Gregarious on sandy soil in the plains 
of Cochinchina (Pierre). 
7. Anisoptera costata, Korth., and (8) marginata, Korth. 
Gregarious on the hills of South-east Borneo (Korthals). 
9. Dryobalanops aromatica, Gaertn. f.—Gregarious in Sumatra 
(Korthals). . 
10. Hopea ferrea, Pierre.—In one place in Lower Cochinchina 
gregarious, covering an entire hillside (Pierre). 
11. H. Recopei, Pierre.— Gregarious, covering entire mountain- 
sides in the province Bienhon, Cochinchina (Pierre). 
12. Pentacme suavis, A. DC.—In Lower Burma scattered, 
chiefly in the forests of Dipterocarpus tuberculatus; gre- 
garious in Upper Burma (J. W. Oliver) and in Cochin- 
china ( Pierre). 
13. Shorea robusta, Gaertn. f.—Forms nearly pure forests of 
great extent at the foot of the Himalaya, extending in 
