120 



TROPICAL PLANTS 



Lake of Titicaca, 12,700 feet above the level of the sea; and 

 in the bleak Puna*, even at the very limits of vegetation, the 

 traveller is astonished at meeting with low bushes of cactuses 

 thickly beset with yellow prickles. 



What a contrast between these deformities and the deli- 

 cately feathered mimosas, unrivalled among the loveliest 



children of flora in the matchless 

 elegance of their foliage ! Our 

 acacias give but a faint idea of the 

 beauty which these plants attain 

 under the fostering rays of a tro- 

 pical 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. 



The Porliera hygrometrica foretells serene or rainy weather 

 by the opening or closing of its leaves. 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 — 



Mimos 



"It is my faith, that every flower 

 Enjoys the air it breathes." 



Among the most remarkable forms of tropical vegetation, the 

 creeping plants, bushropes, or lianas (cissus, bauhinia, bignonia, 

 banisteria, passiflora), that contribute so largely to the impene- 

 trability of the forests, hold a conspicuous rank. Often three 

 or four bushropes, like strands in a cable, join tree to tree, and 



Sec Chapter III. 



