Page:A narrative of travels on the Amazon and Rio Negro.djvu/347

 THE AMAZON VALLEY. 307

any striking flowering tree or shrub. This is partly owing to the flowers of most tropical trees being quickly deciduous : they no sooner open, than they begin to fall ; the Melastomas in particular, generally burst into flower in the morning, and the next day are withered, and for twelve months the tree bears no more flowers. This will serve to explain why the tropical flowering trees and shrubs do not make so much show as might be expected.

From the accounts of eye-witnesses, I believe that the forests of the southern United States present a more gay and brilliant appearance than those of tropical America.

Humboldt, in his " Aspects of Nature," repeatedly remarks on the contrast between the steppes of Tartary and the llanos of the Onnooko. The former, in the temperate zone, are gay with the most brilliant flowers ; while the latter, in the tropics, produce little but grasses and sedges, and only few and incon- spicuous flowering plants. Mr. Darwin mentions the brilliancy of the flowers adorning the plains of Monte Video, which, with the luxuriant thistles of the Pampas, seems hardly equalled in the campos of tropical Brazil, where, with some exceptions, the earth is brown and sterile. The countless beautiful geraniums and heaths of the Cape cease on entering the tropics, and we have no account of any plants equally striking and brilliant supplying their place.

What we may fairly allow of tropical vegetation is, that there is a much greater number of species, and a greater variety of forms, than in the temperate zones. Among this great variety occur, as we might reasonably expect, the most striking and brilliant flowers, and the most remarkable forms of stem and foliage. But there is no evidence to show that the proportion of species bearing brightly coloured, compared to those bearing inconspicuous flowers, is any greater in the tropics than in the temperate regions ; and with regard to individuals — which is, after all, what produces the effects of vegetation — it seems probable that there is a greater mass of brilliant colouring and picturesque beauty, produced by plants in the temperate, than in the tropical regions.

There are several reasons which lead us to this conclusion. In the tropics, a greater proportion of the surface is covered either with dense forests or with barren deserts, neither of which can exhibit many flowers. Social plants are less common