The struggle for independence stopped this traffic, for the upper provinces and the greater part of Peru being in possession of the Royalists to the last, all intercourse with Salta was cut off for many years, nor has there been any sufficient encouragement to renew it since the restoration of peace. Peru, however, must have mules, and it does not appear that she is likely to be supplied with them from any other quarter in sufficient numbers. Proceeding eastward, through the valleys of Campo Santo, and those watered by the Lavayen and its affluents, to Oran, and throughout all that department, a tropical vegetation is found in all its natural luxuriance.[64] Forests of noble trees stud the banks of the rivers, and extend far down the shores of the Vermejo, valuable not only as timber, but as producing fruits which may be said to supply the place of bread and wine to the natives:--such, amongst others, is the algaroba tree, a sort of acacia, from the fruit of which, a large bean growing in clusters of pods, mixed with maize, the Indians make cakes; and, by fermentation, produce their chicha, a strong intoxicating spirit in very general use. The quinaquina, the palm-tree, and the plant from which the famous maté, or Paraguay tea, is made, are equally indigenous there, and many others, as yet only known to us by their Indian names, which it would be useless to recapitulate. The cactus, bearing the cochineal insect, and the aloe are found in every direction:--from the macerated fibres of the latter, the Indians of the Chaco make yarn and ropes, which are found less liable to rot in water than hemp:--their fishing-nets are made of this material, and a variety of bags and pouches, for which there is always a demand amongst their more civilised neighbours: these articles are variously dyed in indelible colours, prepared also by the Indians. There is no doubt that this plant, which grows as commonly in most parts of South America as the thistle with us, might be turned, here as elsewhere, to very considerable account for many useful purposes. I have seen not only beautiful rope, but very good coarse cloth manufactured from it; indeed I have now in my possession some paintings done in Peru upon a canvass made from it, which could not be distinguished from any coarse linen of European make.[65]