160 KELATION BETWEEN CLIMATE AND VEGETATION 



XVI. — Contributions to a History of the Relation hetioeen 

 Climate and Vegetation in various parts of the Globe. 



No. 11. — The Vegetation of Brazil, Bolivia, and Peru. By 

 H. A."Wedde]l, M.D. 



(Translated from tlie Frencli.) 



The environs of the Brazilian capital liave been so often de- 

 scribed by the various travellers who have visited tliem, that it 

 will not be necessary for me to dwell at any great length on 

 them. 



It is difficult to state with clearness the impressions which I 

 experienced when I first entered the forests above Rio, and 

 whicii cover the coast of Brazil. It was not the size so much 

 as the disposition of the plants which surprised me. In this fine 

 climate tlie atniospliere appears to contain within itself all that 

 is required for the healthy being of plants : the most inacces- 

 sible rock, every tree, every branch is a support for a vegetation 

 even more vigorous than that whicli is borne innnediately by 

 the earth. Bromeliads and Orchids without number. Cacti, 

 Arads, Peperomias, Begonias, Gesnerads, and Ferns, are 

 closely packed on the narrow surface on which they grow, and 

 which they soon clothe with a beautiful verdure. 



It would hardly be too much to say that the great Epiphytes 

 of the damp tropical countries * take tlie place of mosses and 

 lichens of more temperate climates. Climbers, which add so 

 much to the character of tropical countries, are found near Rio 

 in every variety : they are so numerous, that in places it is next 

 to impossible to cross the woods. Their stems are generally 

 naked, and can be compared with nothing better than ropes hung 

 from the trees to which they are attached. They often inter- 

 twine, affording each other mutual supjwrt, and rising to the 

 highest attainable point, there to develop their flowers : often 

 they are seen to choke, in their tight embrace, the tree which 

 supports them. 



* At Rio the air is^almost always completely saturated with moisture ; 

 the hair hygrometer generally standing between 80^ and 85°. The lowest 

 temperature we ever observed in this part of Brazil was, in summer, 

 + 17° C, and the highest, in the shade, + 24° C. The mean temperature 

 ascertained by M. Uoussingault's process is 23*5°, and the night tempera- 

 ture is not more than 1" lower than that of the day. 



One might be led to suppose from these ligures that the climate of Rio 

 was tolerably agreeable ; but in addition to the intense heat in the sun, which 

 isj far above anything denoted by instruments, the perfect stillness of the 

 air renders the least exercise extremely fatiguing. 



