422 Expedition to the 



a point about six miles below the confluence of the great 

 river Platte. 



On the precipitous and almost naked argillaceous hills, 

 which here bound the Missouri valley, we found the oxytro- 

 pis lambertii, and the great flowering pentstemon; two plants 

 of jsingular beauty. Here also we saw, for the first time, the 

 leafless prenanthes, the yellow euchromia, and many other 

 interesting plants. It would seem that several species of 

 plants are distributed along the course of the Missouri, but 

 do not extend far on either side. Probably the seeds of these 

 have been brought down from their original localities, near 

 the sources of the river. That the distribution of plants is 

 sometimes effected in this way, there can be no doubt, as in 

 the instance of the portulacca with pilose leaves,* and other 

 natives of of the high and sandy plans of the Arkansa, which 

 are sometimes found transplanted into the deep forests and 

 fertile soils of the hilly region; but the agency of rivers in 

 this respect appears much less important, than without par- 

 ticular examination, we might be inclined to imagine. In 

 ascending the Missouri, the Arkansa, or any great river, 

 every remove of forty or fifty miles, brings the traveller to 

 the locality of some plants, not to be seen below. This is 

 perhaps less the case with rivers running from east to west, 

 or from west to east, than with those whose course in a dif- 

 ferent direction, traverses several parallels of latitude. 



On the 27th, we swam across Mosquito creek, and after 

 a ride of near thirty miles along the Missouri bottoms, 

 encamped near the mouth of the Boyer, about six miles 

 from the wintering place of the party. Early on the following 

 morning, we left our encampment, and were soon after 

 cheered by the report of guns discharging at the Canton- 

 ment. The sight of the trading establishment, called Fort 

 Lisa, gave us more pleasure than can easily be imagined, 



* Nuttall's Travels into Arkansa, p. 165. 



