Page images

It is true that, as they are all low-growing herbs or shrubs with delicate foliage, they might possibly be liable to destruction by herbivorous animals, and might escape by their singular power of suddenly collapsing before the jaws opened to devour them. The fact that one species has been naturalized as a weed over so wide an area in the tropies, seems to show that it possesses some advantage over the gencrality of tropical weeds. It is however curious that, as most of the species are somewhat prickly, so easy and common a mode of protection as the development of stronger spines should here have failed; and that its place should be supplied by so singular a power as that of simulating death, in a manner which suggests the possession of both sensation and voluntary motion.

Comparative Scarcity of Flowers. It is a very general opinion among inhabitants of our temperate climes, that amid the luxuriant vegetation of the tropics there must be a grand display of floral beauty; and this idea is supported by the number of large and showy flowers cultivated in our hot-houses. The fact is, however, that in proportion as the general vegetation becomes more luxuriant, flowers form a less and less prominent feature ; and this rule applies not only to the tropics but to the temperate and frigid zones. It is amid the scanty vegetation of the higher mountains and towards the limits of perpetual snow, that the alpine flowers are most brilliant and conspicuous. Our own meadows and pastures and hill-sides produce more gay flowers than our woods and forests ; and, in the tropics, it is in the parts wliere vegetation is less dense and luxuriant that flower's most abound. In the damp and tropical colonies, more especially as an Indian palm, Phænix sylvestris, also produces abundance of sugar, and might be tried in its native country.

Other articles of food produced from palms are, cooking-oil from the cocoa-nut and baccaba palm, salt from the fruit of a South American palm (Leopoldinia major), while the terminal bud or “ cabbage” of many species is an excellent and nutritious vegetable ; so that palms supply bread, oil, sugar, salt, fruit, and vegetables. Oils for various other purposes are made from several distinct palms, while wax is secreted from the leaves of some South American species; the resin called dragon's-blood is the product of one of the rattan palms; while the fruit of the Areca palm is the “ betelnut” so universally chewed by the Malay's as a gentle stimulant, and which is their substitute for the opium of the Chinese, the tobacco of Europeans, and the cocaleaf of South America.

For thatching, the leaves of palms are invaluable, and are universally used wherever they are abundant; and thic petioles or leaf-stalks, often fifteen or twenty feet long, are used as rafters, or when fastened together with pegs form doors, shutters, partitions, or even the walls of entire houses. They are wonderfully light and strong, being formed of a dense pith covered with a hard rind or bark, and when split up and pegged together serve to make many kinds of boxes, which, when covered with the broad leaves of a species of screw-pine and painted or stained of various colours, are very strong and serviceable as well as very ornamental. Ropes and cables are woven from the black fibrous matter that fringes the leaves of the sugar-palm and some other


and when these are seen from an elevated point looking over an expanse of tree-tops the effect is very grand; but nothing is more erroncuus than the statement sometimes made that tropical forest-trees generully have showy flowers, for it is doultful whether the proportion is at all greater in tropical than in temperate zones. On such natural exposures as steep momtain sides, the Lanks of rivers, or ledges of precipices, and on the margins of such artificial openings as roads and forest clearings, whatever floral beauty is to be found in the more luxuriant parts of the tropics is exhibited. But even in such favourable situations it is not the abundance and beauty of the flowers but the luxuriance and the freshness of the foliage, and the grace and infinite variety of the forms of vegetation, that will most attract the attention and extort the admiration of the traveller. Occasionally indeed you will come upon shrubs gay with blossoms or trees festooned with flowering creepers ; but, on the other hand, you may travel for a hundred miles and see nothing but the varied greens of the forest foliage and the deep gloom of its tangled recesses. In Jr. Belt's Naturalist in Nicaragua, be thus describes the great virgin forests of that country which, being in a mountainous regiou and on the margin of the equatorial zone, are among the most favourable examples. "On each side of the road great trees towered up, carrying their crowns out of sight amongst a canopy of foliage, and with lianas hanging from nearly every bough, and passing from tree to tree, entangling the giants in a great network of coiling cables. Sometimes a tree appears covered with beautiful flowers which do not belong to it, but to one of the lianas tree-ferns, bear their graceful crowns on slender stems twenty to thirty, or even fifty feet high. It is this immense variety rather than any special features that characterises the forn-vegetation of the tropics. We have here almost every conceivable modification of size, form of fronds, position of spores, and habit of growth, in plants that still remain unmistakably ferns. Many climb over shrubs and bushes in a most elegant manner; others cling closely to the bark of trees like ivy. The great birds'-nest fern (Platycerium) aitaches its shell-like fronds high up on the trunks of lofty trees. Many small terrestrial species have digitate, or ovate, or ivyshaped, or even whorled fronds, resembling at first sight those of some herbaceous flowering plants. Their numbers may be judged from the fact that in the vicinity of Tarrapoto, in Peru, Dr. Spruce gathered 250 species of ferns, while the single volcanic mountains of Pangerango in Java (10,000 feet higli) is said to have produced 300 species.

Ginger-worts and wild Bananas.—These plants, forming the families Zingiberacea and Musaceæ of botanists, are very conspicuous ornaments of the equatorial forests, on account of their large size, fine foliage, and handsome flowers. The bananas and plantains are well known as among the most luxuriant and beautiful productions of the tropics. Many species occur wild in the forests ; all have majestic foliage and handsome flowers, while some produce edible fruit. Of the ginger-worts (Zingiberacea and Marantaceæ), the well known capnas of our tropical gardens may be taken as representatives, but the cquatorial species are very numerous and varied, often forming dense thickets in damp places, and adorning the





life. Yet even on the upper surfme of the forest, fully exposed to the light and heat of the tropical sun, there is no special development of coloured flowers. When from some elevatel point you can gaze down upon an unbroken espinse of wooly vegetation, it often happens that not a single patch of bright colour can be discerned. At other times, and especially at the beginning of the dry season, you may behold scattered at wide intervals over the mottled-green surface a few masses of yellow, white, pink, or more rarely of blue colour, indicating the position of handsome flowering trees.

The well-established relation between coloured flowers and the need of insects to fertilize them, may perhaps be connected with the comparative scarcity of the former in the equatorial forests. The various forms of life are linked together in such mutual dependence that no one cap inordinately increase without bringing about a corresponding increase or diminution of other forms. The insects which are best adapted to fertilize flowers cannot probably increase much beyond definite limits, because in doing so they would lead to a corresponding increase of insectivorous birds and other animals which would keep them down. The chief fertilizers-bees and butterflies— have enemies at every stage of their growth, from the cry to the perfect insect, and their numbers are, therefore, limited by causes quite independent of the supply of vegetable food. It may, therefore, be the case that the numbers of suitable insects are totally inadequate to the fertilization of the countless millions of forest-trees over such vast areas as the cquatorial zone presents, and that, in consequence, a large proportion of


« EelmineJätka »