388 
each and averaged 11.5. The average 
number of plants was 335.25 in this size 
unit. 
In the 9-milacre square, the species list 
compiled by 1/4-milacre units showed a 
range of 6 to 12 species and an average 
of 9.27 per unit. The 1-milacre plot size 
had a range of 11 to 16 species each and 
an average of 13.44. Ten species not 
found in the central milacre but found in 
the surrounding eight were Andropogon 
gerardi, Lecidea sp., Aster patens, Eragros- 
tis spectabilis, Rhus copallina, Kuhnia eu- 
patorioides, Panicum scribnerianum, Poa 
pratensis, Ruellia humilis, and a second 
species of Gerardia (possibly G. aspera). 
Twenty-six were found in the 9-milacre 
quadrat. 
The 9-milacre plot formed a part of 
the staked 50-milacre rectangle, fig. 10, 
which was examined by 10-milacre strips. 
Six species not found in the 9-milacre 
square were found in other parts of the 
It~tino1is NatrurAL History SurvEY BULLETIN 
Vol. 26, Art. 5 
rectangle. These were Aster oblongi- 
folius, Opuntia rafinesquii, Tridens flavus, 
Melilotus alba, Rhus aromatica, and Eri- 
geron strigosus. The first four of these 
were found only in the 10-milacre strip — 
nearest the improved pasture eastward 
from the crest of the ridge. This strip, — 
because of its proximity to the pasture, 
probably should not be considered typical 
hill prairie. Two species not found in the 
9-milacre plot were found in other parts 
of the four downslope 10-milacre strips 
and brought the total to 28 species. 3 
The 25-milacre quadrat downslope — 
from the 50-milacre rectangle yielded but — 
one species that did not occur in the 50- 
milacre rectangle; this was Asclepias vir- 
idiflora. “There were, however, seven spe- 
cies in the four downslope 10-milacre — 
strips of the 50-milacre area that did not — 
occur in the 25-milacre unit. These were — 
Rhus copallina, Kuhnia_ eupatorioides, 
Panicum  scribnerianum, Poa _ pratensis, 
ee. ee 
Table 10.—Frequency of occurrence of plant species in plots of five sizes, Sampson hill — 
prairie. 
Size A Size B Size C Size D Size E 
(1/256 (1/64 (1/16 (1/4 al 
Mivacre, Mivacre, MILaAcrE, MILacre, Mivacre, 
0.0156 0.0625 0.25 1.01 4.05 
SQUARE SQUARE SQUARE SQUARE SQUARE 
S Meter) MerTeER) METER) Meters) METERS) 
PECIES 
| 
Num-| Per |Num-| Per |Num-} Per |Num-| Per |Num-]| Per 
ber | Cent | ber | Cent | ber | Cent | ber | Cent | ber | Cent 
of of of of of of of of of of 
Plots | Plots | Plots | Plots | Plots | Plots | Plots | Plots | Plots | Plots 
Andropogon scoparius...... 60 | 93.8 | 64 |100.0 | 16 |100.0 | 36 {100.0 9 |} 100.0 
Houstonia nigricans........ 22 34040 Rae Buel 15 | 93.8 | 36 {100.0 9 100.0 
Desmodium ciliare......... 19 | 29.7 | 42 65.6 16 |100.0} 33 | 91.7 9 100.0 
Solidago nemoralis......... 13! 20032 |= 32 "| 5SOCOn i US 1A9Se See Some ela 9 | 100.0 
Lespedeza capitata......... 1 1.6 5 7.8 5-2) SL. 24 al, 66nd 9 | 100.0 
Gerardia gattingeri(?)...... 1 iF (ey | pews Fa 17.2 8 | 50.0} 20 | 55.6 9 | 100.0 
Bouteloua curtipendula......\| 12 | 18.5 Ly NE D6n6 OP 15655 18 | 50.0 8 88.9 
MEELIA EA SPY ise koko ere ike ote 4 6.3 Broil wees B97 507 07> Su ey 3 77.8 
Andropogon gerardi........ — — 3 4.7 2.21205) ). 1453839 6 66.7 
Petalostemum purpureum.... 1 1.6 8 12.5 ee 438 13°" | =S6e 7 77.8 
Senecio plattensis.......... ~~ — = -- ao Tce OR + 44 4 
Euphorbia corollata........ — — 1 1.6 1 6.3 7 >| Toe 5 55.6 
Agave virginica............ 2 yall 2 3.1 Z, 1255 2 5.6 2 22.2 
Opuntia rafinesquii.........| — — 1 1.6 1 6.3 2 5.6 2 22:2 
ASE DALENS Sos eer oO — — —_ — — 1 Pies! 1 11.1 
COFY2ISD, os 5 aise see ots — — — — — 1 2.8 1 Li 
Sisyrinchium albidum...... — = = - — 1 2.8 1 11.1 
Unidentified moss.........| — — — — — — 1 2.8 1 11.1 
; 
| 10 species 13 species 13 species 18 species 18 species 
| 64 plots 64 plots 16 plots 36 plots 9 plots 
