2 The Botanical Survey of Nebraska 



in all cases much more mesophilous than obtain at our correspond- 

 ing Lincoln stations. Contrasts between the vegetative conditions 

 characteristic of the two areas are remarkable and ecologically 

 very significant although the areas are only about 60 miles apart. 

 These contrasts are clearly shown to be due to striking differences 

 in both edaphic and climatic factors in the two series of stations. 

 This paper also contains many experimental data bearing upon 

 the successional sequence of the various woodland types as com- 

 monly developed in the region about Peru. 



LOCATION OF STATIONS AND DESCRIPTIONS OF PLANT COMMUNITIES 



The descriptions of our stations and of the plant communities 

 prevailing therein have been adequately presented by Weaver and 

 Thiel in the above publication in so far as they pertain to the 

 prairie near Lincoln. The situation is quite different, however, 

 for the woodland habitat at Lincoln and for all of the stations at 

 Peru. Descriptions of these stations and of the plant communi- 

 ties concerned are not incorporated in the former paper hence 

 they must be treated as a portion of the present report. A de- 

 scription of the woodlands at Lincoln follows immediately, while 

 that of the various stations at Peru will be found in the latter por- 

 tion of the paper, which deals in particular with the investiga- 

 tions in that part of the state. 



The station in the woodlands near Lincoln is located in a t3^pical 

 habitat well within the broad-leaved, fringing forest along Salt 

 creek about two miles southwest of the city. Salt creek is a 

 shallow, sluggish stream which drains the broad Lincoln basin, 

 through which it flows in a generally north or northeasterly direc- 

 tion until it enters the Platte river near Ashland about 20 miles 

 northeast of Lincoln. 



The soil along the stream is a fine, dark silt-loam, varying in 

 depth, and in sand and humus content away from the stream 

 banks to the uplands. There is considerable leaf litter covering 

 the surface in the higher, denser woods, while in many low-lying 

 areas practically all surface litter is removed annually during 

 periods of high water. The surface in such periodically flooded 



