CHICAGO AND VICINITT. 



27 



icana), the walnut and butternut (^fuglans nigra and /. cinerea), the 

 pig-nut [Carya porcina). In this rich flood plain forest there are many 

 lianas climbing over the trees, e.g., greenbrier [Smilax hispidd), grape 

 {Vitis — various species), Virginia creeper (^Ampelopsis quinquefolia), 

 and poison ivy [Rhus Toxicodendron). 



Fig. 12. — Mesophytic flood plain forest in the bottoms of the Des Plaines river at Riverside. 

 Elms and basswoods. Rich herbaceous vegetation, consisting largely of Phlox. 



The undergrowth in these river woods is very dense and luxuriant, 

 the alluvial character of the soil making it very fertile. Among the 

 shrubs are the thorns (various species of Crataegus), the gooseberry 

 {Ribes Cynosbatt), and many others. The herbaceous vegetation is 

 dominantly vernal, the shade being too dense for a typical estival flora. 

 Prominent among the spring flowering herbs are Trillium recurvatum. 

 Phlox divaricata, Folemonium reptans, Hydrophyllum Virginicum 

 (Wa.terlea.i), AferUnsia Virginica (Lungwort), Collinsia verna, Claytonia 

 Virginica (Spring beauty), Erythronium albidum (Dogtooth violet), 

 Ariscema triphyllum and A. Dracontium (Indian turnips), Nepeta 

 Glechoma (Ground ivy), Isopyrum biternatum, Caulophyllum thalic- 



