The Solomon Islands and Their Natives Part 32

[423] "Bulletin of the Philosophical Society of Was.h.i.+ngton," 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 ma.s.s 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 ma.s.s 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 c.o.c.kroaches 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 c.o.c.kroaches, but no ants; and, on the outer surface of one of the swollen ma.s.ses, 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.)

[425] This species was obtained at Ugi.

Leaving behind the slime and gloom of the swamp, the rising ground is reached, at the base of which the vegetation is of the most luxuriant character, and often have I lingered here in my Rob Roy canoe to admire the luxuriance of plant-growth that surrounded me. For on account of the lowness of the district, it shares the dampness though not the infertility of the swamps below. The soft clayey rock, which is exposed in the banks of the stream, affords a rich and even too productive soil.

Nature runs riot and becomes prodigal in her profusion; and thus growth is too often a.s.sociated with decay to present on all occasions a pleasing picture to the eye. Here the tree-fern, the croton, the wild plantain, and numerous areca palms flourish; but the alpinias, heliconias, and other scitamineous plants form the chief feature of the vegetation on this gently rising ground.

Higher up the stream, tall forest trees rise on each side often enveloped partially by a drapery of runners and climbing plants, their leafy branches spreading over the water. Stout lianas hang in festoons across the stream. Partly hidden amongst the greater vegetation may be seen the fan-palm of the district (_Licuala_, the "firo" of the natives), and another pretty little palm known as the "sensisi,"

_Cyrtostachys_, together with the handsome foliage of a _Plerandra_ ("fo") and numerous areca palms. An occasional _Dolicholobium_ ("lowasi") with white flowers distributes its fragrance around. Ferns abound along the banks, varying in size from the small _Trichomanes_ to the tree-fern, twenty feet in height, and the _Angiopteris_ with its magnificent spreading fronds fifteen feet and more in length. If one leaves the stream for a few minutes at the foot of the hills, a moist, low-lying district is traversed, the home of the scitamineae and the areca-palms, which latter are distinguished amongst the natives as the "momo," "niga-solu," "niga-torulo," and "au-au."

Ascending the hill slopes towards the source of the stream, numerous palms rise up on either side. The _Caryota_ ("eala") with its branches resembling the fronds of a huge adiantum, the handsome "kisu" (probably a species of _Drymophloeus_) and a tall areca known as the "poamau," are those which frequently meet the eye. Interspersed among them we notice the lesser areca-palms and the fan-palm before alluded to. On the crest of the hill, at a height of some 200 or 300 feet above the sea, are found tall forest trees, some of them of gigantic size and attaining a height of 150 feet and upwards. Amongst them occur the banyan ("chim"), other ficoid trees with the f.l.a.n.g.e-like b.u.t.tresses, and the "katari," a species of _Calophyllum_ which supplies the natives with a resin for their torches. In the following description of the interior of the forest in this region I have referred at some length to the larger trees.

_The interior of the forest... ._ To obtain a true idea of the forest-growth in these islands, it is necessary to traverse one of the more level districts in the interior, which is removed from the vicinity of the cultivated patches of the natives. Entering the confines of the forest direct from the full glare of the tropical sun, one experiences a peculiar and often oppressive sensation, which may be attributed to the combined influences of the warmth, the humidity, and the effluvia arising from the decaying vegetation, to the impressive silence that reigns, and to the subdued light or dusky atmosphere that there prevails. Meeting overhead at a height of some 150 feet from the ground, the foliage and the smaller branches of the lofty trees form a dense leafy screen roofing over, as it were, a series of lofty corridors in which the palms and the lesser trees flourish. The gloom that there prevails is rarely lightened by the direct rays of the sun, except here and there through the gap left by the downfall of one of the huge trunks that now lies rotting on the ground. Nor is the silence that reigns often broken, except by the cooing of the fruit-pigeons overhead or by the rus.h.i.+ng flight of the hornbill startled from its repose. Here the steady blast of the trade is no longer felt and is only perceptible in the movements of the foliage of the tallest trees. Yet there is little in such a scene that would strike the mind of the merely aesthetic lover of nature. Flowers he rarely sees: they are only to be found where the sunlight can reach them in the partially cleared s.p.a.ces in the midst of the forest, or on the sides of ravines, or along the coasts. On the other hand, however, he cannot fail to be impressed by the luxuriance and magnificence of the vegetation in this conservatory of Nature.

Under such conditions the palms flourish. The _Caryota_, the "kisu"

palm, numerous areca-palms, with the tree-fern, give the character to the lesser vegetation. Huge climbing stems, such as the "droau," the "aligesi" (_Aleurites?_), the "nakia" (_Uvaria_), the "awi-sulu"

(_Lyonsia_) lie in coils on the ground and rising vertically reach the lower branches of the trees some fifty to a hundred feet overhead. The large purple papilionaceous flowers of the "droau" sometimes strew the ground at the bases of the tallest trees. If the forest be situated on a hill-side, the slope is clothed by _Selaginellae_ which often display in the midst of their dark-green foliage pretty bleached fronds that form a striking contrast to the prevailing hue. Mosses, small ferns, and fungi, such as the ma.s.sive expansions of _Polyporus_ and the more delicate plates of _Hexagona apiaria_ and others, conceal in some degree the unsightliness of the decaying log. A drapery of lycopods and of trailing and climbing ferns, such as _Trichomanes_ and _Lygonia_ more or less completely invests the lower portions of the trunks of the larger trees.

Seventy or eighty feet overhead the wide-spreading fronds of the birds-nest fern (_Asplenium nidus_) appear half-suspended in mid-air, as they project from their point of attachment to the tree. Lower down the trunk, the handsome aroid _Epipremnum_ may be observed. Epiphytic orchids form no marked feature in this forest-scene, preferring, as they do, those situations where the direct sunlight can reach them, as at the coast and on the sides of ravines. Terrestrial orchids, however, with inconspicuous and sombre-coloured flowers thrive in the gloom and moisture of the forest.

The larger trees, to which I have not yet referred, often attain a height of 150 feet and over. Here the banyan and more than one species of _Canarium_ including the "ka-i" or Solomon Island Almond tree, together with a _Ratonia_ ("nekale"), a _Vitex_ ("fasala"), the "katari"

(_Calophyllum_) before mentioned, and numerous ficoid trees known to the natives as the "uri," the "ilimo," and the "nie," figure amongst the more conspicuous of the forest trees. Many of them possess at the base of the trunk large b.u.t.tresses or f.l.a.n.g.es, which, as in the "tobu,"

"ilimo," "nie," and "maranato" (_Sapotacea?_), may rise twelve to fifteen feet up the trunk and extend some twenty feet away along the ground. Some of the ficoid trees throw off at a height of from twenty to thirty feet, large f.l.a.n.g.e-like b.u.t.tresses, which, on reaching the ground, form natural arches. These lofty trees, as I have already remarked, meet together overhead to form a leafy screen, which, whilst it excludes the direct rays of the sun, admits and confines both the moisture and the heat. This conservatory of nature contains within its own precincts the conditions for its preservation. Here the young tree grows up, its safety ensured, until at length it becomes a pillar in the edifice in which it was itself reared. The open character of the wood and the absence of scrub and undergrowth, more especially on level ground, have often been a cause of surprise to me. I have often walked without impediment through the gloomy corridors of such a forest, brus.h.i.+ng past the huge trunks of the tallest trees, and winding in and out amongst the palms that number as many years in age as their giant compeers count decades.

On first treading in such a forest, the visitor is much impressed by the imposing appearance and size of the banyans and the b.u.t.tress-trees. With mingled feelings of awe and pity he will perceive that between these monarchs of the forest there is waged an unequal struggle, in which the huge b.u.t.tress-tree always succ.u.mbs to the rough embraces of its foe. He will observe all the stages in the struggle. Here the b.u.t.tress-tree may be seen in its prime, but in part embraced at its lower part by the tightly clasping offshoots of the young banyan. Further on, in the midst of the interlacing columns of the banyan, the b.u.t.tress-tree may be seen partially strangled. Dry rot has attacked its trunk reaching almost to the core, so that a sheath-knife sinks readily up to the handle in its substance; yet, far overhead the wide-spreading branches of this forest potentate are covered with green foliage, and still wave defiantly in the trade. In the prolonged contest the b.u.t.tress-tree is dying hard, and in fact it is the stout investing trunks of the banyan that alone hold its victim erect. Near by may be another banyan of larger size and presenting the appearance of a maze of columns which may cover an area thirty to forty feet across. Its victim has long since disappeared, and a hollow in the centre of the maze of stems alone marks the former situation of the huge b.u.t.tress-tree.

What finer or more impressive simile could be employed to ill.u.s.trate the gradual degeneration and final downfall of a nation under the choking influences of vice, corruption, luxury, and misgovernment? A mighty forest tree is slowly strangled by the caresses of an insidious creeper.

With advancing decay its tottering stem is alone supported by the tightening grasp of its foe. Yet its higher branches retain their vitality to the last; and when the end comes, its ashes add fertility to the soil and vigour to the growth of its destroyer.

It is not to be surprised that this battle of the trees should be included in the mythical lore of some of the inhabitants of the Pacific islands. Dr. George Turner, in his recent work ent.i.tled "Samoa, a hundred years ago and long before," gives the following legend of the banyan... ... "A report reached Samoa that the trees of Fiji had fought with the Banian tree, and that it had beaten them all. On this the Tatangia (_Acacia laurifolia_) and another tree went off from Samoa in two canoes to right the Fijian champion. They reached Fiji, went on sh.o.r.e, and there stood the Banian tree. 'Where is the tree,' they inquired, 'which has conquered all the trees?' 'I am the tree,' said the Banian. Then said the Tatangia, 'I have come to fight with you.' 'Very Good, let us fight,' replied the Banian. They fought. A branch of the Banian tree fell, but the Tatangia sprung aside and escaped. Another fell--ditto, ditto--the Tatangia. Then the trunk fell. The Tatangia again darted aside and escaped unhurt. On this the Banian tree 'buried its eyes in the earth' and owned itself conquered."

_An ascent to the summit of the Faro Island... ._ In making an ascent to the higher districts of this island, which attains an elevation of about 1900 feet above the sea, a little may be learned perhaps of the vertical distribution of the coast flora in this portion of the Solomon Group. The cycad (_Cycas circinalis_) grows most frequently just within the trees that immediately line the beach and may be often observed at all heights up to 400 feet above the sea, but it is not usually found at greater elevations.[426] The following large trees commonly occur on the hill-slopes up to an elevation of a thousand feet, the "fasala"

(_Vitex_), the "toa" (_Elaeocarpus_), the "opi-opi," the "ka-i"

(_Canarium_), the "katari" (_Calophyllum_), and others; whilst the palms such as the fan-palm (_Licuala_), the _Caryota_ ("eala"), the "kisu"

(_Pinanga_) and the arecas, fill up the intermediate ground, the fan-palm growing in great numbers and often monopolising the slope.[427]

The smaller trees, of a height usually of sixty or seventy feet, which are more frequently observed during the lower half of the ascent, are, a species of _Cerbera_ ("anumi"), the "kunuka" (_Gnetum_), the "palinoromus" (_Couthovia_), the "poporoko," and others; whilst on the hill-slopes below the elevation of 500 feet the small conifer _Gnetum Gnemon_ ("meriwa") may be commonly seen. In three different localities, at elevations of between 1,000 and 1,100 feet above the sea, I came upon brakes of fine bamboos (_Schizostachyum?_) 35 to 40 feet in length which are employed as fis.h.i.+ng-poles by the natives. This bamboo, both in Treasury and Faro Islands, does not appear to occur below this height; whilst in the Shortland Islands, although found at a lower elevation, it selects the higher regions of the island.

[426] At Treasury Island I found a solitary cycad at a height of a thousand feet above the sea. As it was in the vicinity of a plantation of sago palms, it is probable that it had been planted by the natives who employ the fruits for medicinal purposes.

[427] This fan-palm, the "firo" of the natives, was in 1884 only represented in Treasury by a single individual which had been brought a few years before from Bougainville, where the leaves are employed in making a conical hat that is commonly worn.

Above a thousand feet, many of the trees and palms so frequent below become less common or disappear. The fan-palm (_Licuala_) which grows in such numbers in the lower levels did not come under my notice above this elevation. On account of the absence of large trees near the summit, the lesser vegetation receives more of the sun's rays; and thus at 1,600 feet above the sea the alpinias, such as the "vitoko" and the "kokuru"

re-appear, plants which usually abound in the lower levels in all open situations, as on the banks of streams. For the same reason, we find near the summit of the island at elevations of 1,600 to 1,700 feet the tall composite shrub, _Wedelia biflora_, which is one of the commonest of the plants that grow at the margin of the beach. On account of this absence of large trees, and the consequent increased exposure to the sun's rays, the smaller trees with conspicuous flowers find a congenial situation at this elevation: here are found the species of _Dolicholobium_ ("lowasi"), which is common on the banks of the streams in the lower levels, the _f.a.graea Berteriana_ ("bubulata") which grows also at the coast, a wild nut-meg tree (_Myristica_), a species of _Harpullia_ ("wawaupoko"), the "pakuri" (_Eugenia_), the "baimoloi" and others. In these higher regions tree-ferns grow to a height of thirty feet; and here the areca-palms, "momo" and "niga-torulo," are also found. Here flourishes the _Gleichenia_, a fern which does not usually grow at elevations under 700 feet above the sea, and which is represented by two common species: it is the "sinimi" of the natives who, as I have already remarked, work the fine strips of its vascular tissue into armlets which they commonly wear. Near the summit and all down the slopes is found a species of _Begonia_, a genus, as I am informed by Baron von Mueller, not before recorded from islands east of New Guinea.[428] A dense growth of the trailing stems of a _Freycinetia_ and of ferns clothes the rocky sides of the highest peak, which is almost bare of trees. Here however I found a new genus of the _Pandanaceae_, which, like some other panda.n.u.s trees, is known to the natives as "sararang." It grows to a height of fifty feet, and was only observed by me on the highest peak of the island and for two or three hundred feet below. It has a very conspicuous white "branching female spadix," three to four feet in length; and I learn from Professor Oliver that the same or a near ally of it, though not in a condition to describe, was collected by Signor Beccari in Jobi Island off the north-west coast of New Guinea.

[428] A species of _Ophiorrhiza_ is in Treasury Island usually a.s.sociated with this _Begonia_ and is found at all elevations.

_The coast vegetation of the larger islands... ._ It is in the coasts of such an island as Treasury or Faro Island, where the strictly littoral and more inland plants become intermingled, that the Solomon Island vegetation in some degree redeems its character. Here the prevailing sombreness and inconspicuous inflorescences give place to bright hues and to a variety of flowers. Here are seen the handsome white flowers of a rubiaceous tree, a species of _Bikkia_; the yellowish flowers and bright red fruits of _Harpullia capanioides_ ("koloa"); the crimson flowers of an _Erythrina_ (perhaps _indica_); the yellow flowers of _Caesalpinia Nuga_; the large pods of _Pongamia glabra_; and the fruits of a wild nutmeg (_Myristica_, sp.). _Hernandia peltata_ and _Clerodendron inerme_ may also be here found. The conspicuous flowers of _Hibiscus tiliaceus_, _Thespesia populnea_, and of other littoral trees such as _Cerbera Odollam_ and _Guettarda speciosa_, add their brightness to the scene. Amongst the foliage of the trees twine a species of _Ipoma_ with handsome white flowers, and here are seen the wax-like flowers of more than one species of asclepiad (_Hoya_, sp). Orchids, some of striking beauty, hang from the trunks of the trees and form a conspicuous feature in the scene. Among them occur species of _Dendrobium_, _Coelogyne_, _Cleisostoma_, etc.

_The littoral vegetation, as exhibited in a coral islet... ._ I will take the case of one of the many wooded islets that have been formed on the coral reefs by the action of the waves. On the weather side of such an islet, which may be termed its growing edge, the vegetation is scanty, and there are but few trees. A binding weed and more than one species of _Ipoma_ loosely cover a surface composed almost entirely of calcareous sand, broken sh.e.l.ls, coral debris, and pumice pebbles; and it is on such an unproductive soil that two or more species of _Panda.n.u.s_ and _Casuarina angustifolia_ flourish. Here at the margin of the beach may be seen in profusion the tall composite shrub, _Wedelia biflora_, and another common shrub, _Scaevola Knigii_. Two climbing peas prefer the sandy soil in this situation, one with yellow flowers, _Vigna lutea_, and the other with pink flowers, _Canavalia turgida_; whilst a dense growth of _Flagellaria indica_ often conceals from view any rocky slope overlooking the beach. Just within the line of vegetation immediately bordering the beach, the following trees commonly occur, _Ochrosia parviflora_ ("pokosola"), _Heritiera littoralis_ ("pipilusu"), _Terminalia catappa_ ("saori"), _Cycas circinalis_, and one or more species of _Panda.n.u.s_. Here also a species of _Crinum_ (the "papau" of the natives) and the _Tacca pinnatifida_ ("mamago") may be usually found. (I hoped to have referred to the ferns of such a coral islet; but my endeavours to obtain any information of my collection have been unavailing).

On the lee side of such an islet, which is the oldest portion of its surface, the vegetation is much denser and of a different character.

Here, the trees form a thick belt, their branches overhanging the rising tide. Those of most frequent occurrence are, _Barringtonia speciosa_, _Calophyllum inophyllum_, _Hibiscus tiliaceus_, _Thespesia populnea_, _Guettarda speciosa_, _Morinda citrifolia_, _Cerbera Odollam_, _Pongamia glabra_, _Tournefortia argentea_, and others. The trunks of the larger trees often lean over the beach or lie partly proc.u.mbent on the sand.

Amongst the foliage of these coast trees, many of which have large conspicuous flowers, climbing asclepiads of the genus _Hoya_ with their equally conspicuous flowers may be frequently observed. Orchids, often of considerable beauty, hang from the reclining trunks of the trees.

Here, as in the case of the coasts of the large islands, we perceive how pleasant is the contrast which the littoral vegetation presents when compared with the gloomy and apparently flowerless forests, where the tallest trees possess but an inconspicuous greenish inflorescence.

In the interior of such a coral islet, huge banyans and other trees having wide-spreading b.u.t.tresses are to be found. Many of them attain a height of 150 feet and upwards, and afford a home to numbers of fruit-eating pigeons which largely subsist on their fruits, and through whose agency the interiors of coral islets are stocked with these large trees. Conspicuous amongst the trees is a species of _Canarium_ (the "ka-i" of the natives), the disgorged nuts of which frequently strew the ground beneath; a banyan (_Ficus_) with large oblong fruits and another species with small spherical fruits; other ficoid trees with large b.u.t.tresses, such as the "uri"; a species of _Eugenia_, probably a variety of _Eugenia jambos_; together with several other trees.

This description of the vegetation of a coral islet brings me to refer to the manner in which such an islet, which is usually of very recent origin, has become stocked with its plants: and in so doing I shall be treating of a very important matter, _the oceanic dispersal of plants_.

Fortunately for me, my notes and collections relating to this subject had an increased value at the time of my arrival in England, and in this respect I have been able to accomplish one of the princ.i.p.al aims of a young traveller, that of supplying trustworthy materials to those engaged in the particular line of research to which his notes and collections relate.[429]

[429] Mr. Botting Hemsley was on the point of completing his report on the oceanic dispersal of plants in connection with the Botany of the "Challenger" Expedition. Such of my collections, as referred to his work, were placed at his disposal by Sir Joseph Hooker; and my notes were incorporated in volume I. of the Botany of the "Challenger" (Part III. p. 309), to which I must refer my readers who are more specially interested in this subject.

The picturesquely wooded islets of these seas have been stocked through two princ.i.p.al agencies. Winds and currents drift to their sh.o.r.es the fruits and seeds of the littoral trees which ultimately form the margin of the vegetation; whilst the fruit pigeons disgorge the seeds or fruits of those often colossal trees which occupy the interior.

I will first refer to the former of these agencies. Lines of vegetable drift, intermingled with floating pumice, are frequently observable whilst cruising among the islands of the Solomon Group. The floating fruits commonly found belong to the most familiar littoral trees of this region, those of _Barringtonia speciosa_ and _Calophyllum inophyllum_ being especially frequent; and on more than one occasion the solitary fruits of the former were noticed at sea by Lieutenant Oldham and myself at distances of from 130 to 150 miles to the southward of the group, being probably derived from one of the islands of the New Hebrides to the eastward. Other fruits or seeds occurring frequently in the drift are those of _Nipa fruticans_ and of two or more species of _Panda.n.u.s_; numerous beans (species of _Mucuna_, _Canavalia_, _Dioclea_), the long germinated seeds of the mangrove (_Rhizophora_), an occasional cocoa-nut, the cones of _Casuarina equisetifolia_, _Terminalia catappa_, _Lumnitzera coccinea_, _Guettarda speciosa_, _Ochrosia parviflora_, _Heritiera littoralis_ and others.[430]

[430] Other fruits found floating were a second species of _Calophyllum_, a species of _Gomphandra_, _Harpullia_ sp., and some _Scitamineae_.

The foregoing seeds and seed-vessels with many others may be observed washed up by the waves on the surface of the bare sandy islets or sand-keys, which exhibit the first stage in the growth of those picturesquely wooded coral islets that are ultimately formed on the reefs. On such a sand-key, not more than some 25 or 30 yards across, I have counted as many as 30 different kinds of seeds and fruits, all collected together in the centre, which was only washed over at spring-tides. One of the first trees to establish itself is the mangrove (_Rhizophora_), which by its reclaiming agency adds to the area of the islet and enables other trees, such as _Lumnitzera coccinea_, to take up their abode. _Pari pa.s.su_ with the seaward extension of the reef, the islet increases in size; and in time the winds and currents bring other fruits and seeds which germinate and form ultimately the belt of littoral trees bordering the beach. In this manner _Barringtonia speciosa_, _Calophyllum inophyllum_, _Thespesia populnea_, _Hibiscus tiliaceus_, _Cerbera odollam_, _Ochrosia parviflora_, _Heritiera littoralis_, _Terminalia catappa_, different species of _Panda.n.u.s_, _Casuarina equisetifolia_, and _Cycas circinalis_ with many others referred to on a previous page, become established. It is worthy of note that the fruits of the great majority of trees which form the margin of the vegetation, whether on the lee or weather side of such an islet, float in salt water.[431] The small cones of the _Casuarina_ however, require a certain amount of drying before they can be transported by the waves. The green fruits of the _Cycas_ usually sink in salt water; but I found that one out of ten specimens floated, an exceptional circ.u.mstance which sufficiently accounts for the occurrence of _Cycas circinalis_ on these coral islets.

[431] The results of some experiments I made are given on page 305.

Whilst through the agency of the winds and currents the waves have stocked the islet with its marginal vegetation, the fruit pigeons have been unconsciously stocking its interior with huge trees, that have sprung from the fruits and seeds they have transported in their crops from the neighbouring coasts and islets. Perched up in the branches of the trees, these birds disgorge the seeds they have brought from other localities; and the rejected seeds and seed-vessels lie strewn on the ground beneath. The soft and often fleshy fruits, on which the fruit pigeons subsist, belong to numerous species of trees. Some of them are as large even as a hen's egg, as in the case of those of the species of _Canarium_ ("ka-i") which have a pulpy exterior that is alone digested and retained by the pigeon. The fruits of the banyans and other ficoid trees, which with the _Canarium_ are amongst the most conspicuous trees in the interior of the coral islets, are apparently preferred by the fruit pigeons, since they occur commonly in their crops. A species of _Eugenia_ common in the interior of these islets possesses fruits found in the crops of these birds. Amongst other fruits and seeds on which these pigeons subsist, and which they must transport from one locality to another, are those of a species of _Elaeocarpus_ ("toa"), a species of laurel (_Litsea_), a nutmeg (_Myristica_), an _Achras_,[432] one or more species of _Areca_, and probably a species of _Kentia_. There is, however, another bird common on these coral islets, the ground pigeon _Geophilus nicobaricus_, known commonly as the Nicobar pigeon, which transports seeds in its gizzard cavity that on account of their hardness are not fed upon by the ordinary fruit pigeon (_Carpophaga_). The peculiar structure of the gizzard, which is described on page 323, enables the Nicobar pigeon to crack seeds that can only be broken by a sharp blow with a stone. I have found inside this organ, the hard red seeds of a leguminous plant, very probably _Adenanthera pavonina_, of which one seed is occasionally found to be cracked. We may therefore consider that many small hard seeds and seed-vessels, which would be refused by the common fruit pigeon of these islands, are transported from one locality to another in the gizzard cavity of the Nicobar pigeon.

[432] I am indebted to Mr. Charles Moore of Sydney N.S.W., for the identification of this fruit. (_Vide_ also "Journal and Proceedings of the Royal Society, N.S.W.," XVII., p. 226.)

From the foregoing remarks it may be inferred that the pigeons in these islands play a very important part in the dispersal of plants, to which, as Mr. Botting Hemsley remarks in his report (page 313), they have perhaps contributed more than any other animal. In the Solomon Islands the fruit pigeons, as dusk approaches, frequent the islets on the coral reefs in great numbers, and from their unwillingness to leave their roosts in the trees they fall an easy prey to the sportsman. In one afternoon, on one of the islets of Choiseul Bay, 57 birds fell to the guns of Lieutenant Heming and Lieutenant Leeper; and it is to these two officers that I am indebted for my opportunities of collecting the fruits taken from the crops of these pigeons.

In drawing my botanical remarks to a close, it may be fitting to recall the more lasting impressions which I have received of the vegetation of these islands; and I may do so in a very few words. The characteristic features of the vegetation are to be found in the number and variety of the areca palms; in the abundance of the alpinias, heliconias, and other scitamineous plants; in the imposing size and form of the banyans and the b.u.t.tress trees; and in the profusion of the ferns. I have not previously dwelt upon the important part which the ferns take in the vegetation of these islands, because I had hoped to have heard something of my collection which I presented to the British Museum eighteen months ago; but, to my great chagrin, I have been unable, after repeated application, to learn anything concerning it. I may here state that ferns abound everywhere; in moist and dry situations; in sheltered and exposed districts; now decking the tree-trunks with their draperies, or concealing the unsightliness of the decaying log; here covering the bare slopes of some lofty hill-top, or clothing the surface of some treeless tract. The tree-fern and the wide-spreading _Angiopteris_ are to be found on the banks of streams or in some inland dell. The former avoids the coast, and occurs at all elevations up to 2000 feet and over: it flourishes at the heads of valleys.

LIST OF PLANTS COLLECTED IN THE ISLANDS OF BOUGAINVILLE STRAITS, SOLOMON GROUP, DURING 1884.[433]

[433] I am mainly indebted to the kindness of Professor Oliver for the list of the plants collected by me in the Solomon Islands, most of which were sent to Kew. The ferns are in the British Museum, but I can learn nothing of them. Fortunately, the fungi were not included; and for a list of them I am indebted to Mr. Baker. Most of the orchids, and some of the asclepiads, were given by me to Baron von Mueller, who intends to examine them in connection with subsequent collections. I take this opportunity of expressing my sense of the great kindness he showed me with reference to my plant collections. To Signor Beccari I am also indebted. Owing to my inexperience in botanical collecting, the specimens were often inadequate for descriptive and specific determination; but my deficiencies will appear more excusable when I state that I devoted my attention more particularly to the trees. Professor Oliver, however, informs me that, in spite of its defects, my collection gives an excellent conception of the flora of the islands visited.

ANONACEae.

Uvaria, sp... vulgo "Nakia." A stout climber.

GUTTIFERae.