August, 1955 
Table 2.—Species and numbers of plant in- 
dividuals in the central milacre of Sampson 
hill prairie. 
Evers: Hitt Prairies oF ILLINOIS 
383 
_ Table 3.—Species and numbers of plant in- 
dividuals in the central milacre of Phegley hill 
prairie. 
NuMBER OF PLANT N 
SPECIES oes SPECIES eee as 
Andropogon scoparius...... 1,404* Andropogon scoparius...... 849* 
Houstonia nigricans........ 141 Solidago nemoralis......... 270 
Desmodium ciliare......... 80 Lespedeza stipulacea........ 71 
Solidago nemoralis......... 64 Bouteloua curtipendula...... 56* 
Bouteloua curtipendula..... 44* COR WR oe Bane 29 
Andropogon gerardi........ 14* Petalostemum purpureum.. . 15 
| TALS TS ae eee 11 Houstonia nigricans........ 13 
Petalostemum purpureum.... 9 Desmodium ciliare......... 11 
Lespedeza capitata......... Lespedeza capitata......... 8 
Agave virginica............ 2 Euphorbia corollata......... 6 
Euphorbia corollata......... 1 Cassia fasciculata.......... 4 
Opuntia rafinesquit......... 1 Juniperus virginianat...... 3 
_ ASR 0)) ere L/2s Linum sulcatum........... 3 
Senecio plattensis.......... 1 
ae Polygala verticillata........ 1 
+ Possibly G. gattingeri. Hedeoma hispida........... 1 
10 different species were mapped and 
counted; in the central milacre of Pheg- 
ley prairie, +36 plants of 14 species. Table 
2 shows density for both grass and non- 
grass species in the mapped Sampson mil- 
acre; table 3 gives similar information for 
species in the mapped Phegley milacre. 
Total Densities—In Sampson prairie, 
the density in the mapped central milacre 
was 1,949 plants; in Phegley, 1,341. 
In both prairies, grass-plant individuals 
were more numerous than the nongrass 
plants. In Sampson, 75 per cent of the 
plant individuals were grasses and 25 per 
cent were not grasses; in Phegley, 67 per 
cent were grasses and 33 per cent were 
not. It is of interest that the nongrass 
species made up a higher percentage of 
the individual plants in grazed prairie 
than in ungrazed. 
Ground Space of Plants.—Ground 
space of plants is considered here as the 
area occupied by the plants at ground sur- 
* Estimated. 
T Possibly G. gattingeri. 
£ Small seedlings. 
face. The writer determined the ground 
space for grasses, table 4, from the maps 
of the central milacre of Phegley and 
Sampson prairies by use of a planimeter. 
Phegley Prairie—In the central mil- 
acre of this pastured prairie, dndropogon 
scoparius covered at ground level 1,107 
square inches (71 square decimeters*), or 
17.64 per cent of the milacre; Bouteloua 
curtipendula occupied 138.4 square inches 
(9 square decimeters), or 2.21 per cent 
of the milacre, tables + and 6. The two 
bunch grasses covered 1,245.4 square 
inches (80 square decimeters), or 19.85 
per cent of the quadrat at ground level. 
Most of the plants other than grasses, 
437 individuals of 14 species, occurred in 
the spaces between the grass bunches. The 
*Metric equivalents in this section on ground space are 
given to the nearest whole number. 
Table 4.—Ground space or areas (square inches) occupied at ground surface by the bunch 
grasses in the central milacre of Sampson and of Phegley hill prairies. 
SAMPSON PRAIRIE 
PHEGLEY PRAIRIE 
e ele Andro- Andro- | Bouteloua Andro- | Bouteloua 
pogon pogon curti- Total pogon curti- Total 
scoparius | gerardi pendula Scoparius | pendula 
BmnICHeS......... 1,678.0 8.7 18.8 1,705.5 945.0 112.4 1,057.4 
Isolated shoots... . 103.0 1.3 10.5 114.8 162.0 26.0 188.0 
ho 1,781.0 10.0 29 .3 1,820.3 | 1,107.0 138 .4 1,245 .4 
