112 



DISTRIBUTION OF PLANTS. 



attributed to the " reflection of the all-pervading yellowish dusty soil 

 in the clear blue of the atmosphere." 



On the 20th, we left Santiago soon after 4 A. m., journeying in the 

 same wheel-carriages Eastward ; towards the Zodiacal light, which 

 was very distinct. At the end of " five leagues," we arrived at the 

 spot where the snow-carts for supplying the city are loaded ; and 

 where it became necessary to take horses. Continuing on, the ascent 

 proved gradual and very constant ; the vegetable growth unchanged 

 except in the ravines ; where the QuiUaia and KagenecJda were now 

 prevalent ; and two or three EscalJonias not before met with also 

 attained the dimensions of small trees ; while of intermingled shrubs, 

 the smooth variety of Rhus? causiica became frequent, and a leafy 

 CoUeiia, a softly-pubescent Rihes, and a Buddleia, first made their 

 appearance. The Eccremocarpus scaher, an ornamental woody vine, 

 growing on the ground in detached dense beds, was seen only on this 

 basal portion of the Andes. 



Chaeacter and composition of the Vegetable Growth. From the 

 sea to the middle region of the Andes, as far as the vegetable growth 

 came under observation, there seemed to be seven prevailing Tribes 

 of plants, occurring in the following order of frequency : 



1. Compositce. Including one species that forms a tree ; and several, 

 becoming large shrubs more or less arborescent. 



2. Gmminacece. Very generally diffused throughout the country; 

 but at the time of our visit, chiefly withered and dry. Including in 

 the ravines and low ground, some large reedy species : as the Chusquea 

 or dwarf bamboo, a Deyeuxia, and a Phragmites. 



3. Leguminosce. Consisting principally of shrubs. 



4. Lahiatm. Unexpectedly in this Tribe of plants, consisting prin- 

 cipally of large shrubs. 



5. RMnanthacew. Consisting chiefly of herbaceous species; but in- 

 cluding some large shrubs. 



6. Rhamnacece. Holding the sixth place; from the frequency, 

 wherever bushes occur, of the Colletias. 



7. Myrtacece. Chiefly large shrubs ; some of them arborescent, and 

 one species becoming a tree of medium size. 



Next in order, the following Tribes of plants were observed to be 

 abundant : the Azaras, all of them shrubs ; Rosacea}, including the 

 QuiUaia and KagenecJda, and some herbaceous and humble genera ; 

 Onagracece, from the frequent Fuchsias and Oenotheras; Cactacece, 



