358 VESTAL: A BLACK-SOIL PRAIRIE STATION 
and most of the species of the mixed consocies occur here also, and 
no separate list is accordingly given for the Silphium growth. The 
areas labeled Silphium-Allium prairie in the map belong to this 
consocies. Local abundance of Allium cernuum is frequently seen 
in mesophytic prairie-grass of very rich, moist soil. This may be 
called the Allium society. Allium canadense sometimes replaces 
Allium cernuum. Certain species not listed from the two stations 
above mentioned appear in the following table: 
ADDITIONAL SPECIES OF MESOPHYTIC PRAIRIE-GRASS 
If Hypoxis hirsuta, h lf Stachys palustris, h 
lf Oxalts stricta lf Eupatorium perfoliatum 
la Viola papilionacea la Helianthus grosse-serratus 
1 Asclepias syriaca f Achillea Millefolium 
la Convolvulus sepium i Senecio Balsamitae 
i Physostegia virginiana, h 
The swamp-prairie or fen associationn—The hydrophytic 
extreme of prairie-grass passes insensibly, in places, into marsh 
associations; in other places there is conspicuous zonation, the 
boundaries following contour lines about depressions. One of 
the most distinctive appearances of swamp prairie is the Liatris 
spicata consocies, which has been rather fully described by Gates.* 
Scattered representatives of the blazing-star prairie are found in 
eastern Du Page County, though formerly they were more abun- 
dant. There is also a mixed consocies, variable in composition, 
in which umbellifers are frequently prominent. The meadow rue, 
Thalictrum dasycarpum, sometimes marks a well-defined zone. 
The species typical of the hydrophytic prairie are here listed. 
Many of them persist as relics in mesophytic growths. 
SPECIES TYPICAL OF SWAMP PRAIRIE OR FEN 
1 Calamagrostis canadensis f Asclepias incarnata, ch 
1 Spartina Michauxiana i Asclepias Sullivantit 
| Glyceria nervata f Phlox pilosa 
1 Cyperus sp. ] Veronica virginica 
* Gates, F. C. The vegetation of the beach area in northeastern Illinois ni 
southeastern Wisconsin. Bull. Ill. State Lab. Nat. Hist. 9: 255-372. (Liatris 
Spicata prairie, pp. 301-303.) 1912. 
