NATURAL AREAS AND REGIONS 



471 



earthworms (Helodrilus tenius) and 

 (Diplocardia singularis) are common to 

 this region. 



b. Prairie or Oak-Grove Savanna 



The deciduous forests in central 

 Illinois were scattered in the midst of 

 a rich grassland or prairie. The bound- 

 ary between the two was composed of 

 shrubs and small trees, such as haw- 

 thorn, dogwood (Cornusflorida), bladder 

 nut (Staphylea trifolia), raspberry (Ru- 

 bus occidentalis), and bitter sweet 

 (Celastrus scandens), which formed a 

 strip about 15 or 20 ft. wide. There 

 were thousands of miles of these forest 

 edges in Illinois when the white man 

 first took possession of the land. They 

 were the haunt of the skunk (Mephitis 

 nigra), Franklin ground-squirrel (Citel- 

 lus franklinii), jumping-mouse (Zapus 

 hudsonius), chipmunk (Tamias striatus), 

 and short-tailed shrew (Blarina brevi- 

 cauda), and were also the chief nesting 

 places of a host of birds which now 

 inhabit orchards, yards, and hedges. 

 The elk (Cervus canadensis) was fond 

 of the forest edge. Many of the insect 

 pests of fruit-bearing trees and shrubs 

 originally lived in this transitional area 

 of shrubs and small trees. 



The prairie proper was a rich grassland 

 composed of such grasses as Andropogon 

 furcatus, Andropogon scoparius, various 

 species of Panicum, etc., together with 

 such herbs as the compass plant (Sil- 

 phium laciniatum) , the prairie dock 

 (Silphium terebinthinaceum) , and vari- 

 ous species of golden-rod. The great 

 prairie area was astride the Illinois 

 River where its general direction was 

 east and west. The larger portion, 

 south of the river, was about three 

 times as large as the portion north of 

 the river. The entire northern two- 

 thirds of the state included prairie 

 areas. The bison (Bison bison*), coyote 

 (Cam's latrans}, badger (Taxidea taxus), 

 striped ground-squirrel (Citellus tri- 

 decemlineatus), pocket-gopher (Geomys 

 bursarius), and the prairie rattler 

 (Sistrurus catenatus), were abundant 

 in this region during the period of ex- 



ploration and early settlement. Here 

 also were found the dickcissel, the 

 prairie lark, the meadow lark, small 

 bee-hive snails (Gastrocapta contracta 

 and Pupoides marginatus) , such earth- 

 worms as (Diplocardia communis and 

 Helodrilis trapezoides) and many insects 

 which have now become serious pests 

 of cultivated forage crops and grains 

 (cutworms, aphids, white grubs, etc.) 



c. Local 



In addition to the dominant biota 

 just described, there were local con- 

 ditions. Of these the most important 

 were the sand areas, rivers, lakes, and 

 swamps. 



The sand areas were associated with 

 Lake Michigan and the glacial drainage 

 courses, namely, the Illinois and Kanka- 

 kee rivers, and the swamps with the 

 rivers just enumerated, the Mississippi 

 River, the inter-morainal depressions 

 of the prairie area, and the lake district 

 of the northern part of the state. The 

 sand areas have been the subject of 

 various studies of succession. All stages 

 in the development of the forest and 

 prairie occurred on the sand areas. 

 Here grew several kinds of oaks, cotton- 

 wood, cacti, Monarda, Diodea, Cassia, 

 Rhus and Stenophyllus, and jack pine in 

 the Lake Michigan Region. The fauna 

 of the sandy areas included such animals 

 as the sand lizard (Cnemidophorus 

 sexlineatus), hog-nose snake (Heterodon 

 contortrix), box turtle (Terrapene Caro- 

 lina), many bembecid and sphecoid 

 wasps, such sand frequenting grass- 

 hoppers as (Mermiria neomexicana and 

 Spharagemon wyomingianum), and the 

 cactus feeding syrphid fly (Volucella 

 fasciata). 



Swamps were numerous in the central 

 part of the state in the prairie area. 

 They occupied the depressions in the 

 till of the Wisconsin glacier. Prominent 

 among the plants in the swampy areas 

 were cattails (Typha), bulrush (Scirpus), 

 certain willows (Salix), flags (Iris), 

 swamp milkweed (Asclepias incarnata), 

 Sparganium, and Sagittaria. Among 

 the animals were the muskrat (Ondatra 



