14 NATURAL SCIENCE. Jan., 



DiPTEROCARPS. 



DiFTEROCARPS, or rather some species of the family, are to the 

 tropical forests of Eastern Asia what the pine, the spruce, and the 

 beech are to Europe. That is to say, they are gregarious, forming 

 nearly pure forests of large extent in which one species has got the 

 upper hand, to the exclusion of almost all others. This is the more 

 remarkable since one of the chief characteristics of tropical forests is 

 the great variety of kinds and the isolation of individual species. 

 Thus one member of the family Shorea robusta, the Sal tree, forms pure 

 or nearly pure forests of vast extent at the foot of the Himalaya, from 

 Assam to the Punjab, and in the hills of Eastern Central India. The 

 chief factors which enable this tree to maintain its ascendancy are 

 briefly these. The seed ripens at the right season of the year, at the 

 beginning of the rains, after the forest fires of the hot season ; it is 

 produced in great abundance almost every year and germinates 

 readily. The leaves of the seedlings are very large, and will thus 

 choke other trees and shrubs which have sprung up with them. Last 

 year's seedlings are, moreover, generally strong enough to send up 

 fresh shoots when the rains set in, although they may have been 

 burnt down to the ground by the jungle fires. Finally, the Sill can 

 endure a good deal of shade when young, remaining alive for many years 

 under dense cover of grass, bushes, or trees. Sir Dietrich Brandis has 

 had the advantage of working on the spot, and hence his remarks in the 

 revision of the Order which has just appeared in the Linnean Society's 

 Jouvjial (vol. xxxi.) carry weight. An observation on those species 

 which, though common, do not grow gregariously, but as isolated 

 individuals, often far apart, is of much interest. They are by far the 

 larger number, and many flower and seed abundantly. In three 

 cases, however, in which a great number of seeds were examined, 

 very few were perfect, many were worm-eaten, while in others the 

 place of the embryo was filled up b}' dry, cork-like tissue. The 

 author records a similar peculiarity in another family, Combre- 

 tacese, which produce seed abundantly, but only occur singly in 

 mixed forests. Among large quantities of seed examined only a few 

 contained a perfect embryo. The circumstances which enable 

 certain species to form pure forests certainly promise much interest as 

 a subject of biological research. 



Though Dipterocarps as a rule flower and seed annually, this is 

 not always the case. Mr. Ridley states that in the Malay Peninsula 

 every sixth year is unusually dry, and is characterised by the large 

 number of species which only then produce flower and seed. 



" Miscellaneous Information." 



Few works justify their title more thoroughly than the BiiUeiin of 

 Miscellaneous Information, issued at irregular intervals in connection 

 with the Royal Gardens, Kew. Primarily intended to be "economical 

 and not scientific," its contents have recently consisted, for the most 



