What a contrast between these deformities and the delicately feathered mimosas, unrivalled among the loveliest children of Flora in the matchless elegance of their foliage! Our common acacias give but a faint idea of the beauty which these plants attain under the fostering rays of a tropical sun. In most species the branches extend horizontally, or umbrella-shaped, somewhat like those of the Italian pine, and the deep-blue sky shining through the light green foliage, whose delicacy rivals the finest embroidery, has an extremely picturesque effect. Endowed with a wonderful sensibility, many of the mimosas seem, as it were, to have outstepped the bounds of vegetable life, and to rival in acuteness of feeling the coral polyps and the sea anemones of the submarine gardens.
MIMOSA.
Large tracts of country in Brazil are almost entirely covered with sensitive plants. The tramp of a horse sets the nearest ones in motion, and, as if by magic, the contraction of the small grey-green leaflets spreads in quivering circles over the field, making one almost believe, with Darwin and Dutrochet, that plants have feeling, or tempting one to exclaim with Wordsworth—
‘It is my faith, that every flower
Enjoys the air it breathes.’
Among the most remarkable forms of tropical vegetation, the creeping plants, bush-ropes, or lianas (cissus, bauhinia, bignonia, banisteria, passiflora), that contribute so largely to the impenetrability of the forests, hold a conspicuous rank. Often three or four bush-ropes, like strands in a cable, join tree to tree, and branch to branch; others, descending from on high, take root as soon as their extremity touches the ground, and appear like shrouds and stays supporting the mainmast of a line-of-battle ship; while others send out parallel, oblique, horizontal, and perpendicular shoots in all directions.
No European is able to penetrate the intricate network of a forest thus matted together: astonished and despairing, he stands before the dense cordage that impedes his path, and, should he attempt to force his way through the maze, the strong thorns and hooks with which the tropical creepers are generally armed would soon make him repent of his boldness. The Brazilian planter never thinks of entering the forest without a large knife, or without being accompanied by slaves, who with heavy scythe-like axes attached to long poles, clear the way by severing the otherwise impenetrable cordage.
The enormous climbing trees, that stifle the life of the mightiest giants of the forest, offer a no less wonderful spectacle. At first, these emblems of ingratitude grow straight upwards like any feeble shrub, but as soon as they have found a support in other trees, they begin to extend over their surface; for, while the stems of other plants generally assume a cylindrical form, these climbers have the peculiarity of divesting themselves of their rind when brought into contact with an extraneous body, and of spreading over it, until they at length enclose it in a tubular mass. When, during this process, the powers of the original root are weakened, the trunk sends forth new props to restore the equilibrium; and thus the tough and hardy race continually acquires fresh strength for the ruin of its neighbours.
POLANARRUA.