252 ILLINOIS ACADEMY OF SCIENCE 



cry (Carya ovata), elm (Ulmiis americana) and sugar 

 maple (Acer saccharum). A few other trees such as black 

 and scarlet oaks and black cherry (Primus serotina) are 

 sometimes present in smaller numbers. When not too 

 heavily grazed the undergrowth consists of seedlings of 

 the principal trees, showing that the forest is a permanent 

 one, and of a variety of shrubs among which the panicled 

 dogwood (Cornus ])aniciilat(i ) and the hazel nut (Corylus 

 americana) are the most universally present. The herbace- 

 ous undergrowth is rather varied and rich. A more de- 

 tailed description of the characteristics and composition 

 of a forest of this type will be found upon a later page of 

 this report. 



2. Dry oak forest. — This is usually developed upon 

 areas that are rather deficient in soil moisture, either 

 from their elevation above the surrounding country or 

 because of the poor water holding capacity of the soil due 

 principally to a deficiency of organic matter in the form 

 of humus. A typical forest of this type usually contains a 

 large quantity of black oak (Q. veJutina) the amount vary- 

 ing from 50 to 90 per cent of the stand. White and bur 

 oaks of small size and in small numbers are commonly 

 present. The New Jersey tea (Ceanothus americanus), 

 the false indigo (Amorpha fruticosa) and the maple 

 leaved haw (Vihurnum accrifolium) are commonly the 

 characteristic shrubs, while among the herbs are sunflow- 

 ers, blazing star, prairie clover and golden rod together 

 with such prairie forms as the prairie dock (Silphium 

 tcrehinthinaceum) and the rattle snake weed (Eryngium 

 yiiccaefolitim). 



II. Bottom Land Types. 



These are confined to the river valleys and are developed 

 both upon alluvial and other soils. They, too, may be 

 divided into two types whose development is dependent 

 principally upon the condition of the drainage. 



1. Rich bottom forest. — This type is confined to the 

 lower terraces and well drained flood plains along 

 streams. Its typical trees are walnut (Jiiglans nigra), 

 white, black and green ash (Fraxiniis americana, F. nigra 

 and F. pennsyJvanica), Elm (Ulmus americana), bass- 

 wood (Tilia americana), bitternut hickory (Carya cordi- 



