MESOPHYTES 353 
In northern Illinois the upland forest is generally made 
up of white and red oaks and shellbark hickory; while the 
flood-plain forest contains twenty to twenty-five tree forms, 
Fic. 318.—Junction between an upland forest (oaks on the slope to the right) 
and a flood-plain forest (on the level ground to the left). 
prominent among which are the elms (white and slippery), 
linden (basswood), cottonwood, ash, silver maple, box-elder, 
walnut, and willows (Fig. 318). 
Farther south, from central Illinois, Indiana, and Ohio 
southward, as well as in the Alleghanies, the flood-plain 
forests are the richest known, containing, in addition to 
the forms enumerated above, such prominent trees as syca- 
more, beech, sugar-maple, tulip-tree (white poplar), buck- 
eye, hackberry, honey-locust, coffee-tree, ete. 
In Michigan and Wisconsin the upland forests consist 
prominently of beech, sugar-maple, and hemlock, a char- 
acteristic mixture of deciduous and evergreen trees; while 
the flood-plain forests are scarcely at all developed. 
