522 Part IV. Chapter 3. 
lluvium of the Mississippi consists of detached sandy prairies in places not 
always covered by water. In other places are found?) Acer saccharinum, Ulmus americana, Betula 
nigra, Populus monilifera, Quercus bicolor, Fraxinus viridis, occasionally Quercus rubra and near 
the mouth of Root River Morus rubra and Gymnocladus canadensis (= G. dioica). — The flora 
of the flood plain of the Iowa River consists of Acer dasyca Negundo aceroides 
(= Acer negundo), Ulmus racemosa, U. americana, Fraxinus vieidis, neh monilifera while on 
the second shore line occur Acer nigrum, Juglans nigra, J. cinerea, Ulmus fulva, U. americana, U, 
racemosa, Carya a (= Hicoria minima), Quercus macrocarpa, Q. rubra, Crataegus mollis, 
punctata, Pirus kai ioensis, Prunus americana. — The vegetation of the De s Moines allu- 
i is somewhat similar. Here occur Acer dasycarpum, Negundo aceroides, Ulmus americana, 
Fraxinus viridis, Populus monilifera, Salix amygdaloides, S. nigra, S. longifolia and under the tree : 
shade Leersia virginica, Elymus virginicus, Panicum crus-galli, Pilea pumila, Bidens frondosa, 
Vernonia fasciculata, Aster Brass nti, Nasturtium (Roripa) palustre, Cinna arundinacea and 
Spartina ER Platanus Gerede is absent from the Des Moines alluvium. 
Rocky Ledge Forest Formation. Along the upper slopes of the St. Croix 
sandstone ledges occur Pinus Strobus, Taxus canadensis, Betula lenta, 
while close to the springs Alnus incana occurs. 
On these ledges grow such plants as Phegopteris dryopteris, P. gr Lycopodium 
lueidulum, Asplenium filix-foemina, Nephrodium (Dryopteris) spinulosum var. dilatatum, Pellaea 
gracilis, Mitella diphylla and along the Kickapoo, Sullivantia procumbens, Circaea a Cornus 
eircinata, Arabis nudicaulis, A. racemosa, Acer spicatum, Oenothera fruticosa and Aquilegia 
er 
ocky talus the botanist finds such trees as Pinus Strobus, Betula papyrifera, B. lenta, 
eg cinerea, (Quercus rubra sum Acer nigrum, Juniperus virginiana, and shrubs, 
Amelanchier canadensis, Cornus eireinata, Die Ai triida. Along Pine Creek beneath the trees 
are SIORUBEEN Claytoniana, Cornus eire Re Dierv s Hide, and Cypripedium spertabie, Where 
ra, Quercus alba, Q. Mu ergii (= Q. acuminata), Juniperus virginiana, Acer nigrum, 
Cornus circinata, C. Re Ns mum pubescens, Rhamnus lanceolata and such herbs as, 
Thalictrum dioieum, Lathyrus venosus, L. ochroleueus, Asarım canadense, Cypripedium pubescens, 
Trillium univale, Aralia nudicaulis, A. racemosa, Monarda fistulosa and Eupatorium ageratoides. 
2. The Prairie- and Cliff Formations. 
Prairie Grass Formation. In central Illinois‘) in the oak opening ter- 
ritory two kinds of prairie may be distinguished viz: wet and dry. 
The first plants blooming in the spring on the dry prairies are Draba caroliniana, 
nemone decapetala, Ranunculus faseicularis, Oxalis violacea, Androsace occidentalis; in May, 
Lithospermum angustifolium (= L. linearifolium), L. canescens, L. hirtum (= L. Gmelini), 
‚Troximon cuspidatum, Baptisia leucophaea, Pentstemon pubescens (= P. hirsutus); in June, Viola 
delphinifolia, Seutellaria parvula, Linum sulcatum, Polygala incarnata, P. sanguinea (= P. P. virides- 
sr Asclepias Meadii, A. obtusifolia, Niychkin bermudianum, Tradescantia virginica, Silene 
tirrhina, Mesadenia an tuberosa; in July, Silphium laciniatum, $. terebinthinaceum, 
te Echinacea angustifolia, Ciiesssh palmata, C. lanceolata, Rudbeckia hirta, R. subto- 
mentosa, Lepachys En. Asclepias tuberosa, A. verticillata, Euphorbia corollata, Petalostemon 
violaceus (= P. purpureus), P. candidus, Amorpha canescens, Desmodium illinoense, Ruellia ciliosa, 
Callirhoe en Potentilla arguta, Eryngium yuccaefolium (E. aquaticum); in August, Heli- 
ı) PAMMEL, L. H.: Iloe. cit 
2) BRENDEL, FREDERIC: Flora Peoriana. 1887: 34. 
