: This study is a review of the vegetation of the major plant communities in the wind-blown glacial sand deposits of the lower Illinois River Valley (inland sand deposits of H. A. Gleason). Most of these studies were conducted between 1999 through 2007, with a few into the present. Approximately 1086 km 2 of sand deposits occur on the terraces and uplands surrounding the Illinois River from the “Big Bend” region near Hennepin, Putnam County, south into Greene County, Illinois. These deposits vary in size from a few hectares to the deposit centered in Mason County which covers approximately 570 km 2 . Most sand deposits are now cultivated, with small remnants of protected natural vegetation in nature preserves and a state forest. These natural areas contain many high-quality sand communities, including sand ponds, sand seeps, a tall shrub fen, a sedge meadow, sand prairies, a dry gravel prairie, sand savannas, and sand forests.

Dolomite prairies are rare natural plant communities, with a few high-quality examples in northeastern Illinois. In this study, three dolomite prairies located in southwestern Will County, Illinois, were surveyed to assess species composition and quality. Two of the dolomite prairies were located on the Des Plaines Wildlife Conservation Area (i.e., Blodgett Road Dolomite Prairie Natural Area and Grant Creek Nature Preserve) and the third in the Midewin National Tallgrass Prairie (i.e., Exxon Mobil Natural Area). Overall, a total of 438 taxa were recorded: 318 at Blodgett Road, 255 at Exxon Mobil, and 270 at Grant Creek, with 129 common to them all. Of these, 97 were mesic or wet prairie species, 26 were nonnative taxa, and six were native woody species. Three state endangered and two state threatened species were found associated with these dolomite prairies. The Blodgett Road site was dominated by the annual grass Sporobolus vaginiflorus, along with Andropogon gerardii, Sporobolus heterolepis, and Ambrosia artemisiifolia. The Exxon Mobil site was dominated by the exotic species Poa compressa and Daucus carota, and several native taxa including Sporobolus vaginiflorus, Allium cernuum, Andropogon gerardii, and Solidago altissima. The Grant Creek location was dominated by Sporobolus heterolepis, Rosa carolina, Sorghastrum nutans, and Solidago altissima. These three dolomite prairies can be considered good quality natural areas based on species richness and floristic quality. However, the presence and occasional dominance of nonnative species suggests the need for implementation and continuation of management practices that should maintain or improve their quality.

Pembroke Township, Kankakee Conny, Illinois, is part of an extensive glacial sand deposit. In this part of Illinois, some sand savannas retain much of their original natural character and they have high diversity, we detected 574 taxa of plants, including 11 state-listed endangered and threatened species. On five sites, we evaluated vegetation that varied from dry sand savanna to closed sand forest with Quercus velutina (black oak) dominating the overstory and Q. alba (white oak) the only other species of tree commonly encountered. Density of trees averaged 135.7 stems/ha, with an average, basal area of 7.94 m(2)/ha on our five sites. Based on aerial photographs, the extent of woody overstory has more than doubled since 1939.

The Hooper Branch Nature Preserve is located in the extensive dune and swale topography of the sand deposits of northeastern Illinois. The plant communities present at the time of this survey were similar to those of pre-settlement times. The vegetation associated with the dunes had not been disturbed except for past grazing; the swales, in contrast, were drained and farmed before the area was dedicated in 1986. Dry and dry-mesic sand savanna was associated with the dunes where Quercus velutina (Black Oak) accounted for 75% to 97% of the importance value in the savanna. Carex pensylvanica (Pennsylvania Sedge) was the dominant ground cover species usually followed by Schizachyrium scoparium (Little Bluestem). In parts of the preserve that had been most recently burned, woody species were more common in the ground layer, with the most important being Q. velutina seedlings, Rhus copallina (Dwarf Sumac), and Rubus allegheniensis (Common Blackberry). A 3-ha flatwoods in the Preserve was dominated by Q. palustris (Pin Oak), which accounted for nearly 95% of the overstory.

A survey of vascular plant species at Gooseberry Island Nature Preserve, a 5.56 ha forested island, was conducted during the 2004 growing season. This study was undertaken to document the composition and structure of the vascular flora and to provide baseline information for land management decisions. A young second growth wet floodplain forest and an old-growth mesic floodplain forest community was quantitatively sampled. The wet floodplain forest community was dominated by Acer saccharinum (silver maple) with some Salix nigra (black willow). The mesic floodplain forest was dominated by Aesculus glabra (Ohio buckeye), Acer saccharum (sugar maple), and Quercus macrocarpa (bur oak). Bur oak, a dominant species in the largest tree size classes, was only a minor element in the lower tree size classes and was absent from the shrub and sapling layers. Historical data from 1977 indicate that in the last 30 years there has been a significant increase in buckeye and sugar maple. A total of 162 species in 126 genera and 62 families were encountered, including 35 taxa near the northern limits of their range.

The Iroquois Woods Nature Preserve, located just south of Aroma Park, Kankakee County, is in the Kankakee Sand Area of northeastern Illinois. Three relatively distinct topographic zones exist within the preserve (low terrace, shallow depression, high sand terrace). The forest overstory in all three zones, however, is very similar with most of the same species occurring in each zone, but in different densities. These natural communities are probably due to elevation, distance from the river, soil moisture, and erosion due to flooding events. In the low terrace (mesic sand forest), located near the edge of the Iroquois River channel, Quercus rubra, Tilia americana, Ulmus rubra, Aesculus glabra, and Q. macrocarpa dominate, with the oaks in the larger diameter class. In the shallow depression (wet-mesic sand forest) behind the low terrace Quercus bicolor dominated with 50 stems/ha and accounted for almost half of the total basal area. Tilia americana and U. americana were second and third in importance due to the large number of small diameter individuals. East of the depression was a high sand terrace (dry-mesic sand forest) dominated by Q. alba followed by U. americana, Q. velutina, Prunus serotina, and Q. rubra. This preserve contains one of the few examples of high quality mesic sand forests in the state, but oak regeneration is limited, and shade-tolerant species are becoming more abundant.

The 7.8 km 2 Iroquois County Conservation Area in northeastern Illinois contains many of the plant communities found at this site during pre-settlement times. A sedge meadow, about 2.5 km 2 in size was dominated by Carex haydenii/stricta. The shrub sand prairie was dominated by Carex haydenii/stricta, but nearly 50 species encountered in the plots. In the wet-mesic sand prairies, Rubus hispidus, Euthamia graminifolia, Potentilla simplex and Sorghastrum nutans dominated, while in the dry-mesic sand prairies Rubus hispidus, Schizachyrium scoparium, Vaccinium angustifolium and Sorghastrum nutans were dominant. The ground layer vegetation of the sand flatwood communities was sparse with few species present, Vaccinium angustifolium and Carex haydenii being the most common. The sand savanna communities associated with the dunes had high species diversity. Here the ground layer vegetation varied, depending upon available moisture and shading. In the dry-mesic sand savanna Vaccinium angustifolium, Pteridium aquilinum and Carex pensylvanica were dominant, while in the dry sand savanna Carex pensylvanica, Rhus copallina, Rubus allegheniensis and Schizachyrium scoparium were the important species. This base line data will be used to determine management practices on the conservation area and surrounding nature preserves. Phytologia 91(3) 401-438 (December, 2009).

This study was undertaken to determine vascular plant species composition, vegetation structure, and floristic quality of the major plant communities in the windblown sand deposits of northwestern Illinois during the growing seasons of 2002 through 2005. The major plant communities of the Ayers Sand Prairie Nature Preserve in Carroll County, Big River State Forest in Henderson County, Lost Mound Unit of the Upper Mississippi River Wildlife and Fish Refuge in Carroll and Jo Daviess counties, and the Thomson-Fulton Sand Prairie Nature Preserve located in Whiteside County were examined and the importance values determined for the plant species present. Located on broad terraces of the Mississippi River, these nature preserves and natural areas are remnants of a larger grassland/savanna/forest complex that contained extensive marsh; wet, mesic, and dry sand prairie; sand savanna; and sand forest communities. Most of the sand deposits are now cultivated and the original vegetation is found only in protected remnants, some of which are relatively large. The mature dry sand prairies were dominated by Schizachyrium scoparium; other important species were Opuntia macrorhiza, Dichanthelium villosissimum, Ambrosia psilostachya, and Tephrosia virginiana. Other assemblages of prairie and exotic species were encountered in successional sand prairie communities. Generally, the mature prairie communities in these preserves and natural areas had 35 or more species present in the study plots. Savanna and closed canopy forest communities were also examined. The dry sand savannas were dominated by Quercus velutina and Q. marilandica, dry sand forests were dominated by Q. velutina, and dry-mesic sand forests were dominated by Q. alba and Q. velutina.

A study of the vegetation of Dean Hills Nature Preserve in Fayette County, Illinois was undertaken to document the composition and structure of the vascular flora and to provide information for land management decisions. A total of 313 species in 85 families and 204 genera were collected at the 30-hectare preserve which occurs on a glacial kame and has a rugged ridge and ravine topography. Mature mesic and dry-mesic forest covers much of the preserve. The canopy is dominated by white oak (Quercus alba), red oak (Quercus rubra), and sugar maple (Acer saccharum). Data suggest that sugar maple is regenerating more successfully than the oaks. This same result has been found in several other studies of oak-hickory forests in Illinois. If management such as prescribed burning is not implemented, it is predicted that sugar maple will increase and oaks will decrease in dominance within the preserve.