104 



PHYSIOGNOMY OF PLANTS. 



astonished to find the trees of Cinchona, particular species 

 of Swietenia (Mahogany), Hrematoxylon, Styrax, and balsa- 

 mic Myroxylum, so sparingly distributed. We had occasion, 

 on the declivities of the high plains of Bogota and Popayan, 

 and in the country round Loxa, in descending towards the 

 unhealthy valley of the Catamayo and to the Amazons 

 Eiver, to remark the manner in which the trees which 

 furnish the precious fever-bark (species of Cinchona) are 

 found singly and at considerable distances from each other. 

 The China Hunters, Cazadores de Cascarilla (the name given 

 at Loxa to the Indians and Mestizoes who collect each year 

 the most efficacious of all fever-barks, that of the Cinchona 

 Condaminea, among the lonely mountains of Caxanuma, 

 Uritusinga, and Eumisitana), climb, not without peril, to 

 the summits of the loftiest forest trees in order to gain a 

 wide prospect, and to discern the solitarily scattered slender 

 aspiring trunks of the trees of which they are in search, and 

 which they recognise by the shining reddish tint of their 

 large leaves. The mean temperature of this important 

 forest region, situated in 4 to 4 J S. lat. and at an elevation 

 of about 6400 to 8000 English feet, is from 12^ to 16 

 Eeaumur (60-2 to 68 Mir.) (Humboldt and Bonpland, 

 Plantes equinoxiales, T. i. p. 33, tab. 10.) 



In considering the distribution of species, we may also 

 proceed, without regard to the multiplication of individuals, to 

 the masses which they form or the space which they occupy, 

 and may simply compare together the absolute number of 

 species belonging to a particular family in each country. 

 This is the mode of comparison which Decandolle has 



