CHAPTER XIII.
BOTANICAL NOTES IN BOUGAINVILLE STRAITS.
My botanical collections were made during 1884 in the islands of Bougainville Straits; and in order to add to the completeness of this section of my work, I will briefly refer to the physical character of this locality. The principal islands of this sub-group are Treasury Island, the Shortland Islands, and Faro, or Fauro, Island; whilst around these lie numerous smaller islands and islets. The largest is not more than twelve miles in length, and none of them attain an elevation exceeding 2000 feet, Faro being about 1900 feet, Treasury about 1100, and Alu, the principal of the Shortland Islands, about 500 feet. In geological character they differ widely, Treasury being, for the most part, of recent calcareous formations, Faro of volcanic formations, whilst Alu is formed of rocks of both these classes. Of the numerous smaller islands and islets which dot these straits, some are of volcanic, and others of coral rocks.
In my botanical excursions in these islands, I received the greatest assistance from the natives; and I was particularly struck with the familiar knowledge of their trees and plants which these islanders possessed. They have names for not only nearly all the trees, but for several of the grasses; and, in the case of the former, when I was uncertain as to whether I had come upon any specimen before, they would obtain its flower, or fruit, or foliage, and point out to me its comparative characters. The superior knowledge, which these natives possess of each plant and its uses, has often led me to reflect on the meagre acquaintance with the commonest trees, shrubs, and herbs, which the ordinary white man can claim. Had my native companions asked me to instruct them in a similar manner on the vegetation of an English woodland—if such a rapid change of scene were possible—they would probably have regarded me as a very ignorant and unobservant fellow. They have names for and display a familiarity with many plants that can be of no service to them, a somewhat puzzling circumstance, which may be perhaps explained by their employing instinctively a method of exclusion in the selection of those plants that are of service to them. For the building of his house, the cultivation of his ground, the construction of his canoe, the manufacture of his spears, clubs, and other weapons, and for his many other wants, the native has to resort to the vegetable kingdom for the requisite materials. An extensive acquaintance with the vegetation of his island-home is unconsciously acquired by a native who has himself to provide for all his necessities: but his knowledge extends far beyond that limit which mere utility would appear to demand. In a paper published recently in an American serial,[423] Mr. Matthews combated the notion that savages are versed only in the knowledge of plants and animals that contribute to their wants. He found that the Indians are incomparably superior to the average white man, or to the white man who has not made zoology or botany a subject of study. In this respect, his experience accords with my own. The native of the Solomon Islands will point out by name, in some remote inland dell, an insignificant plant, which, he says, is of no service to him: he names all the weeds of his cultivated patches; and he is similarly acquainted with all the wild fruits, usually distinguishing them by their edible or injurious qualities. Yet, in arriving at such a conclusion, it behoves one to be wary, as I have sometimes found that the native applies the name of a useful plant to all other useless plants (usually of the same genus or family) that resemble it in their more conspicuous characters. Then, again, I have often been surprised at the singular holes and corners in the vegetable world which the native ransacks to supply his wants. A fern that clothes the higher slopes of Faro Island, and which is known to the natives as “sinimi,” and to the botanist as a species of Gleichenia, furnishes the material for their plaited armlets. For this purpose they employ narrow strips of the vascular tissue that forms the firm central portion of the stem. I had previously looked upon this fern as of little use to these islanders, and on learning of the ingenious purpose for which it was employed, I became very careful in the future when pronouncing on the utility or inutility of any familiar plant.
[423] “Bulletin of the Philosophical Society of Washington,” Vol. VII.
With these preliminary remarks, I will proceed to describe the general characters of the vegetation of these islands; and, in order to connect my observations together, I will treat of them in the form of a series of excursions made in different districts.
An ascent of one of the larger streams in the Shortland Islands.—In the lower part of its course, the stream follows a circuitous course amidst the gloom and dismal surroundings of a mangrove swamp. It is difficult to convey in words a true idea of such a scene. The features most imprinted on my memory are those of “a slow and silent stream” of dark turbid water, traversing a swamp of black, repulsive-looking mud, in which the crocodile finds a congenial home. The light of day is subdued into a depressing gloom by the foliage of the mangrove forest: the air, charged with the miasma of decaying vegetable life, is impregnated with a sour, unpleasant odour; and the silence that prevails is interrupted only by the fall of a branch, or by the startled cry of some wading-bird disturbed in its haunt. Nipa palms line the banks in places, and occasionally occupy the swamp for some distance on either side of the stream. Overhead, perched high upon the branches of the tall mangroves, occur the two singular epiphytes, Hydnophytum and Myrmecodia, both of which have been found to be species new to science (H. Guppyanum, Becc.; M. salomonensis, Becc.). From the following remarks, my readers will be able to observe the peculiar features of these interesting rubiaceous plants. The large swollen base of the stem, sometimes eighteen inches in length, is occupied by cavities which are usually infested by ants that actively resent any attempts to carry off their home. It has been considered that this swollen mass and its chambers are due to the irritation produced by the ants gnawing at the base of the young growing stem, and that the plant cannot thrive without the ants; but from observations made by Mr. H. O. Forbes,[424] in Java, on the origin of “this curious-galleried structure” in a species of Myrmecodia, it would seem that this swollen mass and its chambers are produced without the presence of ants, and that in their absence the plant may thrive vigorously. Not unfrequently, I found the ants in scanty numbers, and sometimes they were absent altogether. In the case of Myrmecodia salomonensis, and Hydnophytum inerme,[425] they are found in considerable numbers. The chambers of H. Guppyanum are usually nearly full of dirty rain-water, and contain scarcely any ants, a few cockroaches being generally found in the cavities. Those specimens which I examined of another species of this genus (H. longistylum, Becc.), that occurs on the coast trees, contained a few cockroaches, but no ants; and, on the outer surface of one of the swollen masses, I found a small crab. From my own cursory notes, it would therefore seem probable that these epiphytes may thrive without the presence of ants. . . . . With this digression, I return to my description of the ascent of the stream.
[424] “A Naturalist’s Wanderings in the Eastern Archipelago,” p. 81. (1885.)