Hill Prairies of Illinois’ 
N the sunny, windswept, upper 
( ) ser of some of the bluffs along 
the major [Illinois streams are tree- 
less areas distinctive enough to attract 
the attention of observing travelers. These 
areas are grassy strips or grassy openings 
on the otherwise forested slopes of the 
bluffs, frontispiece. Most of them have 
been little disturbed by man or domesti- 
cated animals. Those that are covered 
with prairie plants are prairies. 
Prairies are grasslands. To many per- 
sons, prairies are flat grasslands. How- 
ever, it is not topography but vegetation 
that distinguishes prairies and other plant 
communities. Forests occur on flat land 
or on slopes. So do prairies. Grasslands, 
or prairies, on pronounced slopes are hill 
prairies. 
The term hill prairies was first used in 
1943 by a University of Illinois botanist, 
Dr. Arthur G. Vestal, in his ecology 
classes and seminars to characterize prai- 
ries that occur on loess bluffs, on mounds, 
on steep, rocky slopes, on steep slopes of 
glacial drift, or on any other steep slopes. 
With few exceptions, the hill prairies of 
Illinois are not hill-top prairies; most of 
them occupy only the upper west- and 
southwest-facing slopes of elevations. 
Most of the once extensive flatland 
prairies have disappeared from the Illinois 
landscape. There yet remain a _ few 
patches of these prairies on the till plains, 
but they have been very much disturbed 
by man or domesticated animals. The 
prairies of the bottomlands, the type stud- 
ied by Turner (1934a, 19346), now occur 
only in small scattered patches, usually in 
field borders or borders of roadside ditches 
in the Mississippi and Illinois river val- 
leys. There are still sizable areas of sand 
prairies of the type studied by Gleason 
(1910), Gates (1912), Vestal (1913), 
*This article is based upon a thesis submitted by the 
writer to the Graduate College, University of Illinois, 
Urbana, in partial fulfillment of the requirements for the 
degree of Doctor of Philosophy in Botany. 
ROBERT A. EVERS 
and others, but the extent of these prairies 
is rapidly decreasing as a result of the ac- 
tivities of man in converting them to fields 
of watermelons or cantaloupes, or to an- 
other type of grassland, the cornfield. 
There remain on the Illinois landscape 
numerous tracts of hill prairie and, as 
these prairie slopes were never plowed, 
they are now the least disturbed type of 
prairie in the state. Although rather com- 
plete studies of till plain, bottomland, and 
sand prairies of Illinois have been pub- 
lished, until this time no comparable study 
has been done for the hill prairies of this 
state. 
Several studies have been _ published 
on the hill prairies of other states. The 
study by Bush (1895) on the mound 
flora of Atchison County, Missouri, and 
the work of Steyermark (1940) on suc- 
cession in Ozark glades of the same 
state concerned, in part, prairie on pro- 
nounced slopes. Studies of Pammel 
(1896, 1899, 1902) and Shimek (1910a, 
19104, 1911, 1924) described the vegeta- 
tion and enumerated the species of the 
loess bluff prairies in western Iowa or of 
the prairie openings or grassy meadows on 
the Iowa bluffs of the Mississippi River. 
Reports of Hanson (1922), of Costello 
(1931), and of Hopkins (1951) described 
prairies on loess bluffs along the Missouri 
River in Nebraska or prairies on loess 
hills in central Nebraska. A paper by 
Marks (1942) characterized what he 
termed the “goat prairies” of Wisconsin 
as prairies located on slopes “‘so steep that 
only the nimble goat could graze them.” 
Sites described in these papers were prai- 
ries on steep slopes, or hill prairies. 
Perhaps the earliest reference in the lit- 
erature to Illinois grasslands on the upper 
slopes of bluffs is found in reports on the 
geology of Greene County and of Scott 
County by Worthen (1868). In these re- 
ports, Worthen described  loess-capped 
bluffs with grass-covered knobs. ‘These 
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