cclxxi 



the Mississippi Valley extends westward as far as our common timber 

 trees do, and down into Texas. 



In this connection, Dr. Engelmann spoke of the change of the character 

 of the original Floras through the agency of man. On the Atlantic coast 

 and in the adjacent country the English settlers evidently introduced many 

 of their weeds, nearly 300 European species being now more or less natu- 

 ralized, more or less widely spread there. Not half of them have thus far 

 made their way to the Mississippi, but every year some new immigrants 

 arrive and make themselves at home here. Spaniards and Frenchmen 

 brought with them to the Gulf coasts a few other intruders, and Spaniards 

 again brought others into California, some of which, e.g. the wild oats 

 (Avena fatua) and the little cranebill {Erodium cicularium) have com- 

 pletely overrun the country, so that for a long time they were considered 

 indigenous. 



In the great seaports, another mode of introduction of foreign plants has 

 lately attracted a good deal of attention ; I mean that by means of the bal- 

 last of ships coming from distant countries, or wool, hides, hay and other 

 products brought by them. Very few of such plants, however, have 

 become naturalized or have spread ; they remain only as temporary or 

 adventitious members of our Flora. 



A recent means of extending the area of plants is through cattle droves 

 from the southwest, and especially through the extension of railroads. In 

 this way a good many southwestern and western plants have found their 

 way into Missouri. Such foreign plants often take hold of extensive 

 grounds as " the fittest to survive," to the detriment of the native Flora. 



It is, therefore, important to observe and note the original Flora of a 

 new region at the time of its first settlement, and then watch the progress 

 of the gradual change which pasturing and cultivation of the soil and the 

 various pursuits of man do produce. I have to some extent done this in 

 this neighborhood, and can say that I have seen great changes in the local 

 Flora during the 45 years in which I have been acquainted with it. Some 

 plants have disappeared, others have come in — and weeds of all sorts have 

 vastly increased : a fit subject for a future paper. 



December 3, 1877. 



The President, in the chair. Twenty members present. 

 The Academy was presented with a mound skull, a stone axe, 

 and two flints, the gift of Capt. W. P. Hall, of the Davenport Aca- 



jg. Muhlenberg ii, which, however, also extends eastward, though in a limited degree. The 

 same may be said of Vitis Labrttsca, which is properly eastern, but is found also on the 

 headwaters of streams flowing westward ; farther west it is represented by V. eestivalis , 

 common to both floras, some western forms of which have often been mistaken for La- 

 brttsca. 



