List of the Vascular Plants at Site M, Cass County, Illinois

K.R. Robertson, L. R. Phillippe, and G. A. Levin
Center for Biodiversity
Illinois Natural History Survey
607 East Peabody Drive
Champaign, IL 61820 USA

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Located about 30 miles northwest of Springfield, Illinois lies one of the state's newest conservation and recreation areas. Known as Site M, this area in Cass County consists of almost 24.5 square miles in a single contiguous holding . Commonwealth Edison Company originally acquired the land for a coal-fired electrical power plant and cooling lake, but decreasing electrical demand eliminated the need for such a facility. In 1993, Site M was purchased by the Illinois Department of Conservation.

Although the land now has a single owner, its history of diverse ownership resulted in a mosaic of habitat types of widely varying natural quality. About half of Site M is cropland, much of which has been leased to farmers. Another 20% is pastureland. Cattle have been removed from most of the Site M, but their impact is clear, not only on the former pastures but throughout the area, including the forests that cover another third of Site M. Still, there are patches of woods that, because of steep terrain, natural barriers like creeks, or the former owners' management, retain higher quality. These forests have a diversity of tree species and sizes, and a higher diversity of spring woodland wildflowers. Botanically the most significant vegetation type on Site M is hill prairie. Found on slopes that are too steep to cultivate, hill prairies require periodic burning to exclude trees and shrubs. The largest series at Site M is found in the Cox Creek Hill Prairie Natural Area, recognized as a Grade B Loess Hill Prairie by the Illinois Natural Areas Inventory. With restoration of adjacent pasturelands that were formerly prairie, this area has the potential to become the largest hill prairie complex in the state.

During 1994, we did extensive field work at Site M to determine the natural quality of the woodlands and hill prairies and to develop a list of vascular plants. We found a total of 593 taxa of vascular plants. All of these were vouchered by herbarium specimens, which are deposited in the herbarium of the Illinois Natural History Survey (ILLS). Of the 593 taxa, 468 are native, while 125 are introduced and include many agricultural weeds, which is to be expected with the extensive row crops and cattle grazing that has occurred at Site M. Undoubtedly there are other plant species present at Site M that we missed, given the large area of Site M. Considering the large number of plants reported for Cass County (1147 species, subspecies, varieties, and hybrids), we had anticipated finding a higher number of species at Site M. However, Site M lacks several plant communities found in other parts of Cass County, such as wet to dry sand prairies, sand ponds, savannas, and high quality wetlands. Further, the list of woodland herbaceous plants for Site M is particularly depauperate.

The following table gives a list of all vascular plants that were observed during field work conducted during 1994 at Site M in Cass County, Illinois.

Genera beginning with A - E are given below.

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Scientific Name Native or Introduced Habitat Frequency of Occurrence Endangered or Threatened Cass County Record
Asclepias verticillata native hill prairies, pastures, hay fields common -- --
Abutilon theophrastiiintroducedagricultural fieldscommon----
Acalypha deamiinativeabove stream banks, on the channel bank, & in creek bedscommon along Cox Creek and a tributary, also along Panther creekthreatenednew to Cass County
Acalypha rhomboideanativefloodplains & stream bankscommon----
Acalypha virginicanativeridge topsinfrequent----
Acer negundonativefloodplainscommon----
Acer nigrumnativeformer home siteone tree seen--new to Cass County
Acer saccharinumnativefloodplainsinfrequent----
Acer saccharum var. saccharumnativewoodscommon----
Achillea millefoliumintroducedpastures & hay fieldsoccasional----
Acorus americanusnativewet areasaw at two area----
Actaea pachypodanativewoodsoccasional----
Adiantum pedatumnativewoodscommon----
Aesculus glabranativewoodsinfrequent----
Agalinis asperanativehill prairiesfrequent on certain hill prairies----
Agalinis skinneriananativehill prairiesfrequent on hill prairiesthreatenednew to Cass County
Agalinis tenuifolianativewet areasinfrequent----
Agastache nepetoidesnativeopen intermitent streamsoccasional----
Agrimonia gryposepalanativewoodsinfrequent----
Agrimonia parvifloranativemoist areas in pasturesoccasional----
Agrimonia pubescensnativewoodscommon----
Agropyron repensintroducedhay fieldinfrequent----
Agrostis gigantea (A. alba)introducedalong streams & hay fieldscommon----
Agrostis perennansnativecreek bankinfrequent----
Ailanthus altissimaintroducedpastureonly 1 tree seen----
Alliaria petiolataintroducedwoodscommon in southern part of area; occasional in northern part--new to Cass County
Alopecurus carolinianusnativehay fieldsinfrequent----
Amaranthus graecizansintroducedwaste areas, roadsidesoccasional----
Amaranthus hybridusnativeedges of crops fieldsfrequent----
Amaranthus retroflexusnativeedges of crop fieldsfrequent----
Amaranthus rudisnativewet areas, roadside ditchesoccasional----
Amaranthus spinosusintroducedcurrent & old pasturesoccasional----
Ambrosia artemisiifolianativebarnlots & old feedlotsoccasional----
Ambrosia trifida var. trifidanativeedge of crop fieldscommon----
Amorpha canescensnativehill prairieseen at 3 hill prairies----
Ampelopsis cordatanativewoods near ridge topsobserved twice----
Amphicarpa bracteata var. comosanativeedge of crop fields & along streamsoccasional----
Anagallis arvensisintroducedstream channelsinfrequent----
Andropogon gerardiinativehill prairiesoccasional----
Anemone cylindricanativehill prairieinfrequent----
Anemone virginiananativehill prairies & woodsoccasional----
Antennaria neglecta var. neglectanativedegraded hill prairieseen only once----
Antennaria plantaginifolia var. ambigensnativewoods & hill prairiesoccasional--new to Cass County
Anthemis cotulaintroducedroadsideinfrequent----
Apios americananativealong streamsoccasional----
Apocynum cannabinumnativepastures, hill prairiesoccasional----
Apocynum sibiricum var. sibiricumnativeroadside at base of seep, wet areasinfrequent--new to Cass County
Aquilegia canadensisnativeroadsiderare----
Arabis glabranativeold fieldinfrequent--new to Cass County
Arctium minusintroducedold home sites & barnlotsoccasional----
Arisaema dracontiumnativewoodsinfrequent----
Arisaema triphyllum ssp. triphyllumnativewoodsinfrequent----
Aristida oliganthanativeold fieldinfrequent----
Aristolochia serpentaria var. serpentarianativewoodsinfrequent--new to Cass County
Aruncus dioicusnativewoodsseen only in and along the edges of one wood----
Asarum canadense var. reflexumnativewoodsoccasional----
Asclepias amplexicaulisnativehill prairieinfrequent----
Asclepias incarnatanativepasture along stream & edge of pondsinfrequent----
Asclepias syriacanativeroadsides, along creeksoccasional----
Asclepias tuberosa ssp. interiornativedirt road on dry hillsideinfrequent----
Asclepias viridifloranativehill prairiesrare, only seen at two locations----
Asparagus officinalisintroducedroadsidesoccasional----
Asplenium platyneuronnativeold fieldscommon----
Aster azureus (A. oolentangiensis)nativehill prairiescommon----
Aster drummondiinativemesic N-facing wooded slopeinfrequent----
Aster ericoides var. ericoidesnativehill prairiescommon----
Aster ericoides var. prostratusnativehill prairiesinfrequent----
Aster lateriflorusnativefloodplainscommon----
Aster novae-angliaenativehill prairies & floodplainscommon----
Aster oblongifoliusnativehill prairiesinfrequent----
Aster ontarionisnativefloodplainscommon----
Aster pilosusnativepasturescommon----
Aster sericeusnativehill prairiesnot common----
Aster urophyullusnativewooded tributary of creeknot common----
Aster x amethystinusnativebase of hill prairieonly seen once--new to Cass County
Astragalus canadensisnativehill prairiesrare, only seen at two locations----
Athyrium angustumnativemesic woodsoccasional----
Barbarea vulgarisintroducedhay fieldoccasional--new to Cass County
Belamcanda chinensisintroducedhill prairies, woodsoccasional----
Bidens bipinnatanativewet areasoccasional----
Bidens cernuanativeedges of pondscommon----
Bidens tripartitanativefloodplains, edges of pondscommon----
Blephilia ciliatanativeopen woods & roadsidesoccasional----
Boehmeria cylindricanativefloodplains, creek bedscommon----
Botrychium dissectum var. dissectumnativeyoung woodsinfrequent----
Botrychium dissectum var. obliquumnativeyoung woodsinfrequent----
Botrychium virginianumnativewoodscommon----
Bouteloua curtipendulanativehill prairiescommon----
Brachyelytrum erectumnativewoodsinfrequent----
Brassica nigraintroduceddisturbed areasinfrequent----
Brickellia eupatorioidesnativehill prairiescommon----
Bromus arvensisintroducedhay fields & roadsidescommon--new to Cass County
Bromus commutatusintroducedhay fields & roadsidescommon----
Bromus inermisintroducedhay fields & roadsidesabundant----
Bromus pubescensnativewoodsoccasional--new to Cass County
Bromus pungensnativepasturesabundant----
Bromus tectorumintroducedhay fields & roadsidescommon----
Cacalia atriplicifolianativehill prairies, roadsidesinfrequent----
Calystegia sepium ssp. americananativealong streams, wet areascommon----
Campanula americananativeinside & edges of woodscommon----
Campsis radicansnativefloodplaininfrequent----
Cannabis sativaintroducedroadsides, pasturesabundant----
Capsella bursa-pastorisintroduceddisturbed areascommon----
Carduus nutansintroducedpastures & hay fieldscommon--new to Cass County
Carex aggregatanativehill prairieoccasional--new to Cass County
Carex annectens var. annectensnativealong streams & wet areascommon----
Carex bicknelliinativeold fieldsinfrequent----
Carex blandanativewoodscommon----
Carex breviornativehill prairiesoccasional----
Carex bushiinativeold fields & upland woodscommon--new to Cass County
Carex cephalophoranativeopen woods & fieldsoccasional----
Carex davisiinativeold fields & roadsidesoccasional--new to Cass County
Carex frankiinativebottomlands, around ponds, edges of streamscommon----
Carex gracilescensnativewoodsoccasional----
Carex granularisnativeseepoccasional----
Carex gravida var. gravidanativefloodplainsOCCASIONAL----
Carex gravida var. lanelliananativehill prairieinfrequent--new to Cass County
Carex griseanativewoodscommon----
Carex hirsutellanativeold fieldsOCCASIONAL--new to Cass County
Carex hirtifolianativewoodscommon--new to Cass County
Carex jamesiinativealong wooded streamsoccasional----
Carex lanuginosanativeseepinfrequent----
Carex luridanativeintermittent streamsOCCASIONAL----
Carex meadiinativehill prairiesOCCASIONAL----
Carex molestanativeroadsides and wet areasoccasional--new to Cass County
Carex muhlenbergiinativeold fieldsinfrequent----
Carex normalisnativehill prairiescommon----
Carex oligocarpanativemesic wooded slopesOCCASIONAL--new to Cass County
Carex pensylvanica var. pensylvanicanativeopen woodsinfrequent, saw only one site----
Carex radiatanativewoodsoccasional--new to Cass County
Carex richardsoniinativehill prairiesrare----
Carex roseanativewoodsoccasional----
Carex shortiananativeseepinfrequent----
Carex sparganioidesnativewoodsoccasional----
Carex stipatanativealong streams & hay fieldoccasional----
Carex teneranativefloodplainsOCCASIONAL----
Carex umbellatanativehill prairiesoccasional----
Carex vulpinoideanativeopen wet areaoccasional----
Carya cordiformisnativewoodscommon----
Carya illinoensisnativeedge of woods2 trees seen----
Carya ovata var. ovatanativeupland woodsinfrequent----
Carya tomentosanativeupland woodsinfrequent----
Cassia fasciculatanativeold fields, roadsidesoccasional----
Cassia (Senna) hebecarpanativeold fieldonly seen once--new to Cass County
Castilleja coccineanativehill prairies, seepinfrequent, seen in 2 areas----
Catalpa bignonioidesintroducedold fieldsinfrequent--new to Cass County
Celastrus scandensnativeedges of woods & bases of hill prairiescommon----
Celtis occidentalis var. occidentalisnativeridge topsinfequent----
Cerastium nutans var. nutansnativedisturbed areasoccasional----
Ceratophyllum demersumnativepondonly seen once----
Cercis canadensisnativewoodscommon----
Chaerophyllum procumbensnativelow woods & along streamsoccasional----
Chamaesyce maculata (C. nutans)nativeroadsides & hill prairiesoccasional----
Chenopodium ambrosioides var. ambrosoidesintroducedcreek bankoccasional----
Chenopodium berlandieri var. zschackeinativeopen intermittent stream between cropfieldsoccasonal--new to Cass County
Chenopodium gigantospermumnativedisturbed woods, along dirt roadinfrequent----
Cichorium intybusintroducedroadsidescommon----
Cinna arundinaceanativefloodplains, creek bottomscommon----
Circaea lutetiana ssp. canadensisnativewoodscommon----
Cirsium discolornativepasturescommon----
Cirsium hillii (C. pumilum)nativehill prairies & former pasturescommon, see special summary of this speciesthreatened--
Cirsium vulgareintroducedwaste areainfrequent----
Claytonia virginicanativewoodscommon----
Clematis virginiananativefloodplaininfrequent----
Commandra umbellatanativehill prairiescommon----
Commelina communisintroduceddisturbed areasoccasional----
Conium maculatumintroducedalong streamsoccasional----
Convolulus arvensisintroducedroadsidesinfrequent----
Conyza canadensisnativepastures & edges of crop fieldscommon----
Coreopsis palmatanativehill prairiesinfrequent----
Coreopsis tripterisnativehill prairiesinfrequent----
Cornus drummondiinativehill prairies, woods, edges of streams & pondsabundant----
Coronilla variaintroducedpasturesinfrequent----
Corylus americananativepastures, woodsoccasional----
Crataegus crus-gallinativeold pastures, edges of hill prairiescommon----
Crataegus mollisnativeold pastures, edges of hill prairiescommon----
Croton glandulosus var. septentrionalisnativehill prairies & bare areas in pasturesoccasional----
Croton monanthogynusnativehill prairies & bare areas in pasturesoccasional----
Cryptotaenia canadensisnativelow woods & ravinescommon----
Cuphea viscosissimanativemoist ravine bottomsinfrequent----
Cuscuta compactanativefloodplainoccasional--new to Cass County
Cynanthum leavenativecrop fieldsoccasional----
Cyperus ferruginescensnativeedge of pondoccasional----
Cyperus lupulinus (C. filiculmis var. micilentus)nativepastures & hay fieldsoccasional----
Cyperus strigosusnativeroadside ditchoccasional----
Cystopteris protrusanativewoodscommon----
Dactylis glomerataintroducedpastures & hay fieldscommon----
Dalea candidanativehill prairiesonly seen on 1 hill prairie----
Dalea purpureanativehill prairiescommon on hill prairies----
Datura stramoniumintroduceddisturbed areasinfrequent----
Daucus carotaintroducedroadsides, hay fields, pasturesabundant----
Delphinium tricornenativewoodsonly seen once----
Dentaria laciniatanativewoodscommon----
Descurainia pinnata ssp. brachycarpanativeroadsidesoccasional----
Desmanthus illinoensisnativepastured hill prairiescommon----
Desmodium canescensnativebottomland degraded woodsinfrequent----
Desmodium cuspidatum var. longifoliumnativehill prairieoccasional----
Desmodium glabellumnativehill prairieoccasional--new to Cass County
Desmodium glutinosumnativedry woodscommon----
Desmodium illinoensenativehill prairies & pasturesoccasional----
Desmodium sessilifoliumnativehill prairiesoccasional----
Dianthus armeriaintroducedhill prairies, pastures, old fieldsoccasional----
Dicentra cucullarianativemesic woodsoccasional----
Digitaria ischaemumintroducedfieldsoccasional----
Digitaria sanguinalisintroducedfields, disturbed areascommon----
Diodia teresnativebare areas in pasturesoccasional----
Dioscorea villosanativeupland woodsoccasional----

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