EVAPORATION CONDITIONS AT SKOKIE MARSH 



EARL E. SHERFF 

 University of Chicago, Chicago, Illinois 



The general ecological conditions at Skokie Marsh have already 

 been described in large measure by Baker, ^ and, more recently, 

 by the present writer.- Only a brief description need be given 

 here. The marsh proper (fig. 1) extends with frequent inter- 

 ruptions from west of Highland Park, Illinois, to west of Winnetka, 

 IlUnois, a distance of about 12 km. A small, meandering stream, 

 the Skokie, enters from the north and during the wet seasons, 

 autumn to spring, is often 1 meter or more deep. 



The plants along the course of the stream constitute a rather 

 narrow but typical reed swamp formation. Among the prom- 

 inent plants here are, Typha latifolia, Scirpus validus, S. flumatilis, 

 Phragmites communis, Sparganium eurycarpum, Sagittaria lat- 

 ifolia, Nymphaea advena, Sium cicutaefolium, Acorus Calamus and 

 7m versicolor. Along each side of the reed swamp occurs a 

 level and, in some places, very broad area of swamp meadow 

 formation. This consists largely of tall perennial grasses, by 

 far the most abundant being Calamagrosiis canadensis, although 

 Glyceria nervata and Phalaris arundinacea are dominant in cer- 

 tain places. Near the margins of the marsh, true meadow is 

 present at a few points; elsewhere, the ground is in use for culti- 

 vation or has become occupied by forest. Typical of the meadow 

 are Poa pratensis, Agrostis alba, Eleocharis palustris, Viola cucul- 

 lata, Equisetum arvense, etc., and the average height of the her- 

 baceous plants is much less than of those in the reed swamp and 

 swamp meadow formations. 



' Baker, F. C, The ecology of the Skokie Marsh area, with special reference to 

 the MoUusca. Bull. 111. St. Lab. Nat. Hist. 8: no. 4. 1910. 



2 Sherff, E. E., The vegetation of Skokie Marsh, with special reference to sub- 

 terranean organs and their interrelationships. Bot. Gaz. 53: 415-435. 1912. 



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