Studies in Prairie and Woodland 3 



areas is covered by a layer of very fine silt containing consid- 

 erable organic matter. 



The vegetation in general is characteristically that described by 

 Pound and Clements^ under " The Bur Oak-Elm- Walnut Forma- 

 tion." The woodlands in question are, however, not perfectly 

 typical of this type as the above authors described it for farther 

 eastward in the state, but they are clearly derived from that " for- 

 mation " as delineated by them. These woodlands exhibit some 

 of the usual well-known variations of the type as it is seen nearer 

 the main body of forest along the Missouri river farther to the 

 eastward. The principal differences most noticeable are a more 

 open stand and fewer dominant and secondary species as com- 

 pared with the typical "formation" in its optimum expression. 

 This vegetation is fairly t3'pical of areas found as tongues of 

 woods following up the numerous stream courses from the Mis- 

 souri river in eastern Nebraska. More or less similar communi- 

 ties may be seen along such streams as Weeping Water creek and 

 the Nemaha river. Such belts of timber vary from a few rods 

 in width to a mile or more wide along their easternmost limits 

 where they merge insensibly into the main body of timber on the 

 Missouri river bluffs and along the valleys to complete disap- 

 pearance at the headwaters of the streams far back in the prairies. 

 Frequently the trees are found only in the immediate proximity 

 of the streams. Such linear belts of woods are clearly the fin- 

 gered extensions of the great main broadleaf forest complex 

 whose center lies in the Ohio valley. 



The most striking floristic contrast among the dominant species 

 of the Salt creek woods as compared with those farther east- 

 ward in the state, as at Peru, is seen in the absence of Quercus 

 rubra and Hicoria ovata which Pound and Clements included 

 among the dominants of their " Red Oak-Hickory formation " so 

 well developed in southeastern Nebraska. The red oak-hickory 

 formation is not represented at all in the woods about Lincoln. 

 Bur oak, Quercus macrocarpa, and the Bitternut hickory, Hicoria 

 minima, are the only representatives of those important genera 



2 Phytogeography of Nebraska. 1898. 



