180 RELATION BETWEEN CLIMATE AND VEGETATION 



plant yields a blue ; and black is obtained from the fruit of the 

 Algarobilla, together with some matter containing iron. Lastly, 

 the inhabitants of this country and of Bolivia in general use the 

 root of the Palillo or Escobedia scahrifolia, instead of saffron, 

 with which the Spaniards so constantly colour their food. 

 At Sauces I observed, for the first time, that it was the custom 

 to chew the leaf of the Coca, which, as is well known, is to the 

 Quiehas and Aymaras inhabitants of Bolivia what the Betel is 

 to the Malays, and Tobacco to sailors of all countries. 



Quitting Sauces on the 24th of December I soon left tlie 

 province of Azero for that of Tomina, when to my dismay I 

 found that the rains had set in. In an attempt to pass the Rio 

 Grande de Chapimayo, myself and company were within an ace 

 of being all drowned. I was thus compelled to force my way 

 through a forest of Myrtles (Sauni) and spiny trees crossed every- 

 where by ravines and bogs ; and then to keep along tlie beds of 

 the Kio Canical, San Lorenzo, Monomai, and Caravallo, which 

 were all nearly full of water, and which I had to ford more than 

 120 times in three days. 



The above statement may give the reader some little idea of 

 the diflftculties I had to contend with — difficulties which were, 

 however, enlivened by the stupendous and magnificent rocks 

 around. The ravines of which 1 have spoken are often walled in 

 by rocks rising perpendicularly to a height of 300 feet, and their 

 surface, kept moist by the ever rising vapour which no wind 

 dispels, is covered with a host of curious plants appearing in relief 

 on a delicate network of Lycopods ; there are, for example, several 

 Gesnerads, rich scarlet-flowered Begotiias, numerous Oxalis, and 

 an immense quantity of lovely Ferns. Almost every tree groAving 

 in this neighbourhood is covered witli the curious Tillandsia 

 usneoides, which, hanging down in long grey festoons like a light 

 moss, gives an almost supernatural cloudy aspect to the forest. 



On leaving the bed of the Rio Caravallo, one of the tribu- 

 taries of the Parabiti, I reached the foot of the celebrated moun- 

 tain (Cuesta) Curi, or Uli-Uli, the highest in the district, and 

 composed, like all the others of this range, of red scliist and sand- 

 stone. At the top of this high ground is the table-land of 

 Tomina, on which is the town of Pomabamba. Unaccustomed 

 as I was to mountain travelling, I trembled when I looked at the 

 frightful paths my caravan iiad to pursue ; the i"oad is often little 

 better than a furrow hollowed on tlie bare face of a perpendicular 

 rock ; at other times it is literally nothing more than a succession 

 of holes sunk in the limestone, and which prevent the feet of the 

 mules from slipping. However, the journey over this mountain 

 was rewarded by a very rich collection of plants which I had 

 never met with in any of my previous expeditions, as might 



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