THE FERN FLORA OF NEBRASKA* 



T. J. FITZPATRICK 



Nebraska lies near the center of the region known as the great 

 plains of North America and near the eastern side of the semiarid 

 district. The boundaries are natural or nearly so. Missouri river 

 forms the eastern boundary, the northern boundary lies in the valley 

 of the Niobrara, the southern in the valley of the Republican, while 

 the western boundary is in the foothills. The range is from the 

 40th to the 43d parallel and the western border is the 104th meridian. 

 The greatest width is 208 miles, the greatest length is 455 miles, the 

 area is 77,530 square miles, of which 712 square miles are water. As 

 to comparative size Nebraska is much larger than all of New Eng- 

 land and considerably larger than England and Wales together. 

 The elevation varies from 785 feet to about 5390 feet. As a whole 

 the state has the aspect of a rolling prairie, there being plateaux and 

 foothills only in the western portion. The annual rainfall varies from 

 35 inches along Missouri river in southeastern Nebraska to 14 inches 

 in the semiarid districts in the western portion. The mean annual 

 temperature varies from 52° F. in the southeastern corner to 45 ** 

 in the northwest corner. The recorded evaporation data give the 

 average annual total amount from April to September inclusive, 

 for Lincoln, during an eleven year period, as 34.8 inches, and for a 

 three year period at North Platte as 4L3 inches. 



The physiographic regions of the state are: (I) river valleys, 

 (2) wooded bluffs, (3) prairies, (4) sandhills, (5) plateau or foot- 

 hill region, (6) pine ridge, and (7) bad lands. 



RIVER VALLEY REGION 



On the eastern side of the state is the narrow valley of Missouri 

 river. It is bordered by steep and wooded blufifs, broken by numer- 

 ous ravines. The width varies from half a mile to as much as 

 eight miles. Missouri river meanders between the bordering bluffs, 

 thus leaving a variable width of valley to the Nebraska side. 

 Horseshoe lakes or lagoons are abundant. The soil is of alluvial 

 origin, being of fine silt and sand. Old woods are common. 



♦Contribution from the Department of Botany, University of Nebraska, 

 New Series, No. 30. 



