NOTE. 



THE following description of genera and species is intended 

 to furnish exercises for the student in practical botany. It is 

 designed to include the most common indigenous and exotic 

 plants ; such as teachers can most readily procure for their 

 classes, .and such as pupils are most likely to meet with in 

 their botanical excursions. Those who expect to go beyond 

 the elements of the science, will find in the Manual of Profes- 

 sor Eaton a complete list of American plants. 



Botanical Districts. 



Eaton considers North America as divided into two botanical 

 districts , northern and southern. The dividing line to be drawn 

 from the mouth of Delaware river (N. Lat. 39, W. Lon. 

 75), to the south end of Lake Michigan (N. Lat. 41 31') ; 

 leaving in the northern district all Pennsylvania, and the north 

 part of Delaware, Maryland and Ohio. The division line thus 

 rises as we go towards the west, because southern plants ex- 

 tend to higher latitudes on the western side of the Allegany 

 range, than on the eastern side. 



The northern district is divided into eastern and western, by 

 a line drawn from the intersection of the Allegany range and 

 the Potomac river, in the direction of Cayuga lake. The 

 Allegany mountain is the dividing line in the southern district. 



Explanation of figures, Letters and characters, used in the 

 Generic and Specific descriptions. 



Numbers. 



The first number following the generic description, is the 

 number of the natural order of Linnaeus, the second number 

 is that of Jussieu. 



Letters* 



E and W are used to denote that the plant is found in the 

 eastern or western division of either of the districts. 



S, at the end of a description, shows that the plant grows in 

 the southern as well as northern district. 



