42 NOTES ON DIPTEROCARPS. 



This relationship of S. robusta to the genus Dipterocarpus 

 finds confirmation in the anatomy as determined by Heim. Heim, 

 (Recherches sur les Dipterocarpacees, Paris, 1890, p. 40), having 

 divided Shorea into nine sections, and having put S. robusta into 

 the first of them, called Eu-Shorea, wrote of it, " This section 

 seems to make connection with the genus Dipterocarpus especially 

 by reason of the distribution of its vascular bundles in the leaf- 

 stalk, and in the number of resin canals; but in the shape of the 

 stamens it diverges more than do other sections such as Antho- 

 Shorea!' 



Unfortunately of Heim's En-Shoreas there are many species 



yet to study. 



S. robusta at its best, where the drainage is excellent and the 

 soil is deep, makes pure forests, of a beautiful dark green, and 

 -often with the ground coated by seedlings struggling up under the 

 parent trees. Hole (Indian Forest Records, v., part 4, p. 52) has 

 found that the seedlings will grow healthily under an artificial 

 shade which reduces the light to .015, demonstrating so how well 

 the species is able to tolerate, when young, the deep shade those 

 forests, wherein it asserts itself continuously against other 

 trees. This power of making pure forests is possessed by some 

 other Dipterocarps ; Dipterocarpus itself possesses it, and Dryo- 

 balanops Camphora, and Shorea assamica, none in competition 

 against another, but each in its own particular geographic region: — 

 8. robusta round the rim of the Bengal plains, S. assamica in Up- 

 per Assam, Dipterocarpus chiefly through Burma, Siam and Indo- 

 China, and Dryobalanops in Sumatra, Borneo and the Malay Penin- 

 sula. 



Some observers have written of the success of Shorea robusta 

 as connected with forest fires. Gamble pointed out that it drops 

 its seeds after the season of fires is over, and shares the profit got 

 thereby in its less pure forests with Stereospermum chelonoides — a 

 rather constant companion which sheds its seeds at the same time. 

 Brandis (Forest Flora XIII, p. 53) remarked that the reproduc- 

 tion of Sal may be materially increased by the circumstance that 

 the seed falls after the fires have passed. Many foresters, the last 

 Troup (Indian Forester, 1916, p. 57), have pointed out that if fire 

 is withheld the coating of dead leaves on the forest floor prevents 

 the sprouting seeds from sending their roots down, and betrays them 

 by drying rapidly when a dry spell comes. Others have pointed to 

 the way in which a coating of grasses and other herbs may hold 

 the seed from off the ground by its wings, so that it germinates in 

 the air, to be dried up soon: and that as these leaves and grasses 

 are destroyed by the fires, a way is thereby prepared for the seed. 



Haines (Indian Forester, 1917, p. 311) has stated that fires 

 are advantageous in another direction, namely that they diminish 

 the abundance in the forests of the fungi which attack Sal. 



Jour. Straits Branch 



