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VESTAL: A BLACK-SOIL PRAIRIE STATION 363 
_ to contain the following plants: thorn-apple, occasional at the 
edge of the forest; dogwood, in a narrow and interrupted zone next 
the trees; occasional shrubs of black raspberry (Rubus occidentalis) ; 
lianes (Rhus Toxicodendron, Vitis vulpina, and Psedera quinquefolia), 
climbing on some of the outer shrubs and trees; tall herbs (Veronica 
virginica, Campanula americana, Geum strictum); other herbaceous 
plants, some being prairie plants common near forest areas (Mo- 
narda mollis, Pycnanthemum virginianum), some common in 
swamp prairie (Thalictrum dasycarpum, Oxypolis rigidior). Less 
mesophytic borders, particularly at northwest-facing forest edges, 
are transitional between shaded and very exposed borders, the 
Cornus and Helianthus zones usually being present, but often very 
narrow. Additional secondary species of infrequent occurrence 
are seen. 
A disturbed south-facing border near the railroad track has the 
sunflower zone partially replaced by Canada blue-grass (Poa 
compressa). Scattered shrubs of Rosa humilis, Rhus glabra, and 
blackberry (Rubus sp.) are invading the grassland at some little 
distance from the woods. 
Summary.—The county line station, a half-hour’s ride west of 
Chicago, contains areas of prairie, forest, and forest border in still 
fairly good condition. Preservation of the forest from former 
prairie fires is suggested by its location on the east side of a line of 
prairie sloughs. The prairie, like that of other stations in this 
part of Illinois, is largely mesophytic; this type is of three appear- 
ances: (1) the Andropogon furcatus prairie, (2) the mixed grass 
Prairie, and (3) the Silphium terebinthinaceum prairie. Meso- 
phytic prairie-grass may be derived either from marsh growths and 
Swamp prairie or fen, small areas of which are still abundant near 
by, or from xerophytic prairie-grass, represented in the area chiefly 
by Silphium laciniatum prairie. The markedly xerophytic types 
of prairie-grass no longer persist in upper Wisconsin glaciation of 
northeastern Illinois, but are well represented in central and 
western parts of the state. Sunny forest borders show an outer 
zone of sunflowers, a shrub zone of dogwood, occasionally with 
hazel or alder, and sometimes a low-tree zone, in which plum, 
thorn-apple, or wild crab may be seen. Shaded borders show less 
definite and narrower zones, with tall mesophytic herbs, climbers, 
and usually dogwood. 
UNIVERsITy oF COLORADO. 
