June 1891.] BOTANICAL SOCIETY OF EDINBURGH. 129 



system, which traverses the Chaco pampean plain from 

 North to South along its eastern margin. Of tlie three 

 rivers I have mentioned, the largest and most important, 

 from the physiographical standpoint, is the Bermejo. The 

 Pilcomayo has, however, within the last few years been 

 attracting much attention from an economic point of view, 

 owing to its possible utility as an outlet to Bolivia, in the 

 event of its navigability. An important question thus 

 came to be, " Is the Pilcomayo navigable, or is it not ? " and 

 with the object of settling this question, a large expedition 

 was fitted out in Buenos Aires in the latter part of 1889. 

 Special steamers were built in this country for the expedi- 

 tion, and everything was placed under the command of an 

 Argentine Officer — Captain John Page ; and this expedition 

 I received permission to accompany, in the role of naturalist. 



Leaving Buenos Aires in the beginning of 1890, several 

 weeks were occupied in steaming up the Eio Parana. 

 Arrived at Eesistencia, the military capital of the territory 

 of the " Chaco," some time further was spent in completing 

 preparations ; and on February 26th a final start was made 

 for the Pilcomayo. A short run was made up the river 

 Bermejo for the purpose of testing the boats, so it was not 

 until March 12th that the Expedition actually entered the 

 Eio Pilcomayo. The expedition at this time consisted of 

 some 80 men altogether, including an escort of 50 Argentine 

 soldiers ; and was embarked upon two steamers — stern- 

 wheelers of light draught, specially built. The smaller of 

 these vessels, the " Bolivia," was that destined for the 

 actual work of exploration, the larger boat having to be 

 left behind at a very early stage, owing to her size and 

 unwieldiness. 



One of the remarkable features of the part of the world 

 now under consideration is the extraordinary sharpness of the 

 limit between civilisation and utter wilderness : on the one 

 side of the Eiver Paraguay is the country of Paraguay, thickly 

 populated and highly civilised ; on the other, scarcely half a 

 mile distant, is the Chaco, peopled only by a few wandering 

 Indians. On entering the Pilcomayo, then, it was with 

 feelings that we were for, at the least, several weeks bidding 

 absolute good-bye to civilisation, and to all contact with the 

 outer world. The river itself impressed one not so much 



TEANS. EOT. SOC. VOL. XIX. K 



