355 
Ridley. — On the Dispersal of Seeds by Wind. 
fruit might be hurried on ; D. oblongifolius is the only exception I know. 
It lives on the banks of streams, and the fruits drift down, and I have even 
seen them in the sea, but dead. Yet several species range from the mouth 
of the peninsula to Banka and Borneo. Dryobalanops aromatica , Gaertn., 
occurs in three localities in the peninsula only, so far as is known, and is 
confined to small areas in those localities. They are at Rawang in 
Selangor, on the west of the peninsula; Endau river, Johor, and Kwantan 
in Pahang in the east of the peninsula ; and it is also abundant in Borneo 
and the Philippines; so that to reach Rawang from Kwantan (about no 
miles, going in a straight line) under the most favourable circumstances 
it would take 58,300 years, and from Borneo (300 miles further) 266,710 
years. This seems almost incredible, but it is improbable that the tree 
moved even as fast as this. Dipterocarpus grandifolius , Blanco, ranges 
from the peninsula to the Philippines, and if we assume that at the time 
of its migration the Philippines were connected by land with the peninsula, 
the shortest way the plant could go would occupy 1 J million years. The 
fruit of this tree, however, is much heavier than that of Shorea , and it is 
improbable that it would drift with the wind as far as 100 yards. The 
whole area of the wing-fruited Dipterocarpeae extends from Burmah to the 
Philippine Islands. The most widely distributed seem to be — 
Dryobalanops aroinatica , Gaertn. Rawang, Malay Peninsula, to the 
Philippines. 
Anisoptera glabra , Kurz. Yoma, Cambodia, and Cochin China to 
Singapore. 
Anisoptera costata,- Korth. Singapore to South-east Borneo. 
A. Curtisii , King. Penang to North-west Borneo. 
Dipterocarpus Griffithii , Miq. Mergui, Andamans, to Pahang. 
D. Hasseltii , Bl. Malacca to the Philippines. 
D. pilosus , Roxb. Assam to Sumatra and Banka. 
D. grandiflorus , Blanco. Penang, Banka, Philippines. 
Hopea Pierrei , Hance. Cambodia, Singapore, and Borneo. 
Shorea furfur ace a , Miq. Malay Peninsula, Sumatra, Banka, Philippines. 
S. gratissima, Dyer. Tenasserim to Singapore. 
N. leprosula , Miq. Perak to Singapore, Sumatra, and Borneo. 
The short distance to which these winged fruits or seeds drift is not 
confined to Dipterocarpeae, as will be illustrated by observations on plants 
of other orders. 
Terminalia subspathulata , King (Combretaceae), is a lofty tree as much 
as ico feet tall. It is endemic and rather local. The fruit is flat, thin, 
oblong rounded, one inch long and two inches across, with a single seed in 
the centre. 
When detached by the wind it drifts along, rotating round its long axis 
and sometimes rising a little if the gust is strong. I found its limit of 
