ON THE DISPERSAL OF. PLANTS. 275 
and Direction Islands, where they once thrived, the lover of 
nature might have found some consolation for the destruction 
of the rest. 
_ Now and then, however, the old order of things asserts 
itself, as when newly formed tracts of sand, which have been 
added to these islands, receive their first vegetation. A 
coarse grass, assisted by such creeping plants as Jpomea 
pes capre, Triumfetta procumbens, and Triumfetta subpalmata, 
first clothes the surface, which is soon after occupied by 
bushes and young trees of Yournefortia argentea, Sccevola 
henigii, and Morinda citrifolia, over the foliage of which 
Ipomea grandiflora frequently spreads. When these islands 
were first occupied, Morinda citrifolia was scantily re- 
presented; but having been re-introduced for commercial 
purposes, which have been long since abandoned, it now 
threatens to over-run every island.* .... A tendency to 
return to the original condition of things is again to be seen 
in the localities where the observant eyes of the proprietor 
or of those under him have not been cast for sometime. For 
the crabs, who ably assist Mr. Ross in keeping all vegetable 
intruders out of the islands, as I shall subsequently show, 
sometimes turn against him in the war of extermination, and 
do their best whilst storing the fruits of Hernandia peltata 
and other trees in their holes in the ground, to scatter the 
seeds far and near over the surface of the island. Hence the 
recrudescence of the Hernandia in islands not visited for some 
time, and the subsequent wrath of the proprietor..... 
Before proceeding to refer to North Keeling Island, mention 
should be made of Casuarina equisetifolia, introduced into the 
Settlement Island more than half a century ago by the 
grandfather of the present proprietor, and now spreading by 
natural means. Reference should also be made to another 
tree, Suriana maritima, which within the last 20 years has 
established itself through natural agencies on the weather 
margin of Gooseberry Island. 
North Keeling Island, the vegetation of which I will now 
briefly describe, as I have before observed, has never been 
visited by a naturalist. It is a small atoll rather over a mile 
in length, and has an opening on its eastern side leading into 
a shallow lagoon. Its soil is richly impregnated with guano, 
and great numbers of frigate-birds, boobies, gannets, and 
other sea-birds, still occupy parts of the island. The effect 
* It was thus overlooked by Darwin in 1836, but recorded in 1878 by 
Forbes. 
