Page  85 ï~~2003 THE MICHIGAN BOTANIST 85 NEW COUNTY RECORDS FOR PLANTS OF THE CHICAGO REGION Thomas G. Lammers Department of Biology and Microbiology University of Wisconsin Oshkosh Oshkosh WI 54901 lammers @uwosh.edu The region surrounding Chicago, Illinois, is one of the most heavily urbanized in the nation, and at the same time one of the most fascinating botanically. Within a 75 mile radius of the downtown "Loop," an area encompassing 22 counties in four states and about 11,000 square miles, may be found plant communities representative of the eastern deciduous forest, boreal conifer forest, and tall-grass prairie, as well as numerous disjunct elements from the Atlantic Coastal Plain. Over 1600 species and varieties are native to this region, and another 900 are naturalized. The most recent summation of the flora of the Chicago region (as defined above) is provided by Swink and Wilhelm (1994). This compendium provides a wealth of empirical information on the ecology and biogeography of the plants of the region, including a county-level distribution map for each taxon recognized. During a nine year residence in suburban Chicago (1990-1999), I collected a number of plant specimens in counties from which the respective species had not been reported by Swink and Wilhelm (1994). With my departure from the region, it seems appropriate to publish these county records, with an eye toward their inclusion in future editions of the book. For consistency and convenience, all nomenclature used herein follows that used by Swink and Wilhelm (1994). In cases where it seems useful, I have emulated their practice of listing associated species found in the same habitat with the species of interest. Alopecurus geniculatus L. (Poaceae) Marsh Foxtail ILLINOIS. Will Co.: Bolingbrook, Indian Boundary Park, north of Boughton Rd. and east of Naperville Rd., abundant in wet ditch on floodplain of East Branch DuPage River, between the two westernmost youth baseball diamonds, 4 Jun 1995, T G. Lammers 9371 (F, ISC, MU, OSH). This European grass was first collected in the region in 1970, and has been reported from only DuPage and McHenry Counties, Illinois; and Kenosha Co., Wisconsin. At the site reported here, it was the dominant grass, filling a ditch 2 m wide and over 30 m long, to the near exclusion of all else. Aster prealtus Poir. (Asteraceae) Willow Aster ILLINOIS. Will Co.: Jackson Twp., along railroad tracks parallelling State Hwy 53 (old US Hwy 66), just north of its junction with Hoff Rd., 0.8 mi. S of Elwood, scattered in mesic prairie, 9 Oct 1994, T G. Lammers 9289 (F, TEX).

Page  86 ï~~86 THE MICHIGAN BOTANIST Vol. 42 A somewhat frequent species in the region, reported from low meadows, thickets, and fens in nearly all counties. Associated species at the Will County site included Andropogon gerardii Vitman, Aster ericoides L., A. laevis L., A. novae-angliae L., A. pilosus Willd., Coreopsis tripteris L., Eupatorium altissimum L., Lespedeza capitata Michx., Parthenium integrifolium L., Physostegia virginiana (L.) Benth. var. arenaria Shimek, Pycnanthemum virginianum (L.) T. Durand & B. D. Jacks., Ratibida pinnata (Vent.) Barnh., Solidago rigida L., Sorghastrum nutans (L.) Nash, and Spartina pectinata Link. Carex muskingumensis Schwein. (Cyperaceae) Swamp Oval Sedge WISCONSIN. Racine Co.: Caledonia Twp. T4N R22E S3, along small creek flowing into Root River from the north, east of the railroad tracks and north of 7% Mile Rd., just south of the Milwaukee Co. line, muddy riparian forest, 27 Aug 1999, T G. Lammers & N. A. Harriman 10804 (MU, OSH). This sedge is not infrequent in the region, occurring in woods near major streams and in wooded depressions among glacial moraines. At the site reported here, associated species in the herbaceous layer included Acalypha rhomboidea Raf., Carex grayii Carey, Laportea canadensis (L.) Wedd., Leersia virginica Willd., Mimulus ringens L., Penthorum sedoides L., Physostegia virginiana (L.) Benth. var. virginiana, and Rudbeckia laciniata L. Cuscuta campestris Yuncker (Convolvulaceae) Field Dodder ILLINOIS. Will Co.: Bolingbrook, along Schmidt Rd. at the Lily Cache Creek culvert, parasitic on Convolvulus arvensis L. on weedy roadside, 31 Jul 1993, T G. Lammers 8869 (F, ILL, MU). This holoparasite occurs occasionally in the region in disturbed sites; introduced Convolvulus arvensis is the most frequent host plant. Reported from only Cook, DuPage, Grundy, Kankakee, and Lake Counties, Illinois; and Porter County, Indiana. Duchesnea indica (Andrews) Focke (Rosaceae) Indian Strawberry ILLINOIS. Will Co.: Bolingbrook, along S bank of Lily Cache Creek, just E of the Schmidt Rd. culvert, weedy disturbed floodplain woods, 2 May 1998, T G. Lammers 10625 (BRIT, F, MU, OSH). An Asian species, naturalized in disturbed often shaded sites in several counties in the region. Swink and Wilhelm (1994) comment that it is "slowly but surely becoming more frequent in the Chicago region." Elymus riparius Wieg. (Poaceae) Riverbank Wild Rye ILLINOIS: Cook Co.: Palos Twp., Swallow Cliffs Woods Forest Preserve, SW of the junction of US Hwy 45 and State Hwy 83, low open area at head of ravine NW of parking lot, 26 Sep 1997, T G. Lammers 10435 (F, ISC). A frequent but perhaps undercollected species, occurring in calcareous woodlands, espcially along bluffs of streams and rivers. Associated species in the herbaceous layer at the Cook Co. site included Bidens frondosa L., Boehmeria cylindrica (L.) Sw., Glyceria striata (Lam.) A. S. Hitchc., Leersia virginica Willd., Muhlenbergia frondosa (Poir.) Fern., Pilea pumila (L.) A. Gray, Poly

Page  87 ï~~2003 THE MICHIGAN BOTANIST 87 gonum cespitosum Blume var. longisetum (Bruyn) Stewart, P punctatum Ell., P virginianum L., and Scrophularia marilandica L. Euphorbia serpens HBK (Euphorbiaceae) Round-leaved Spurge ILLINOIS. Will Co.: Channahon Twp. T34N R9E S26 W%, ponds southeast of the junction of Drummond Rd. and West Patrol Rd., east of the railroad tracks, 3% miles west of Elwood, in the Midewin National Grassland (formerly the Joliet Army Ammunition Plant), bare mud on drying pond bottom, 10 Sep 1997, T G. Lammers 10370 (F, MU, NY). This report is not strictly speaking a county record. However, this species was reported from the region solely on the basis of an unvouchered 1964 observation by Floyd Swink. Swink's locality was either at or very near the site from which the present voucher was obtained. Associated species included Amaranthus tuberculatus (Moq.) Sauer, Bidens comosa (A. Gray) Wieg., Conobea multifida (Michx.) Benth., Cyperus acuminatus Torr. & Hook., Eleocharis acicularis (L.) Roem. & Schult., Helenium autumnale L., Lippia lanceolata Michx., Ludwigia palustris (L.) Ell. var. americana (DC.) Fern. & Grisc., L. polycarpa Short & R. Peter, Lycopus asper Greene, Penthorumn sedoides L., Polygonum hydropiper L., P hydropiperoides Michx., P lapathifolium L., P pensylvanicum L., and Scutellaria lateriflora L. Lonicera morrowii A. Gray (Caprifoliaceae) Morrow's Honeysuckle ILLINOIS: Will Co.: Jackson Twp., along railroad tracks parallelling State Hwy 53 (old US Hwy 66), just north of its junction with Hoff Rd., 0.8 mi. S of Elwood, degraded mesic prairie, 21 May 1995, T G. Lammers 9333 (F, MU, NA, OSH); Bolingbrook, along S bank of Lily Cache Creek, just E of the Schmidt Rd. culvert, weedy disturbed streambanks, 28 Apr 1998, T G. Lammers 10622 (BRIT, F, NA). Grundy Co.: Braceville Twp., along State Hwy 53 (old US Hwy 66), 5.6 mi. SW of its junction in Braidwood with State Hwy 113, just SW of the bridge over Mazon River, common on margin of deciduous woods, 31 May 1997, T G. Lammers & A. M. Mahoney 9898 (F, NA). Though this cultivated Asian species is widely nauralized in North America, in the Chicago region it has been reported from only Cook, Lake, and McHenry Counties, Illinois; and Walworth County, Wisconsin. Malus prunifolia (Willd.) Borkh. (Rosaceae) Plum-leaved Crab ILLINOIS. Will Co.: Bolingbrook, along S bank of Lily Cache Creek, just E of the Schmidt Rd. culvert, weedy disturbed floodplain field, 2 May 1998, T G. Lammers 10626 (BRIT, F, MU, NA). This cultivated Asian species was first collected in the region as a naturalized plant in 1987. It has been reported only from DuPage and Kane Counties, Illinois. Malva alcea L. (Malvaceae) Vervain Mallow ILLINOIS. Will Co.: Bolingbrook, along Lily Cache Creek, south of Cumberland Dr., brushy thickets, 1 Jul 1995, T G. Lammers 9480 (F, MU).

Page  88 ï~~88 THE MICHIGAN BOTANIST Vol. 42 This European species has been collected as a naturalized plant in the region only once previously, in Kane County in 1989. Myriophyllum spicatum L. (Haloragidaceae) European Water Milfoil ILLINOIS. Will Co.: Bolingbrook, pond (excavated no more than 3 yrs earlier) just SE of the intersection of Weber Rd. and Lily Cache Lane, abundant in shallow water, 27 Sep 1997, T G. Lammers 10453 (F). This naturalized Europe species was first collected in the region in 1970. Since that time, it has become all too common in ponds and lakes, both artificial and natural. Panicum columbianum Scribn. (Poaceae) Hemlock Panic Grass ILLINOIS. Will Co.: Custer Twp., along State Hwy 53 (old US Hwy 66), 2.6 mi. S of the bridge over the Kankakee River in Wilmington, sandy ditch, 17 Jun 1993, T G. Lammers 8750 (F, ILLS, ISC, MU, MWI). Frequent in sandy soil and dunes of the eastern portion of the region but much more scarce in the western portion. Associated species at the Will County site included Allium canadense L., Phlox glaberrima L. var. interior Wherry, and Oenothera pilosella Raf. Polygonum aviculare L. (Polygonaceae) Common Knotweed ILLINOIS. Will Co.: Bolingbrook, 520 Princeton Dr., in bluegrass lawn, 19 Sep 1997, T G. Lammers 10385 (F, MU). An infrequent weed of disturbed ground, native to Europe, and known in the region from only Cook, DuPage, and Kane Counties, Illinois; and Jasper, Porter, and Starke Counties, Indiana. Salixfragilis L. (Salicaceae) Crack Willow ILLINOIS. Will Co.: Bolingbrook, along S bank of Lily Cache Creek, just E of the Schmidt Rd. culvert, weedy disturbed streambanks, 28 Apr 1998, T G. Lammers 10620 (BRIT, F, MU, NA). A native of Eurasia, not infrequently escaped from cultivation in the region. Samolus parviflorus Raf. (Primulaceae) Water Pimpernel WISCONSIN. Racine Co.: Caledonia Twp. T4N R22E S3, along small creek flowing into Root River from the north, east of the railroad tracks and north of 7% Mile Rd., just south of the Milwaukee Co. line, infrequent on bare mud in riparian forest, 27 Aug 1999, T G. Lammers & N. A. Harriman 10791 (MU, OSH, WU). Rare in the region, occurring on muddy floodplains and in shaded ditches at scattered localities. For a list of associated species at this site, see Carex muskingumensis above. This species, treated as Samolus valerandi L. subsp. parviflorus (Raf.) Hult6n, is shown at www.botany.wisc.edu as occurring in Wisconsin only in Milwaukee County.

Page  89 ï~~2003 THE MICHIGAN BOTANIST 89 Silphium integrifolium Michx. x S. terebinthinaceum Jacq. (Asteraceae) ILLINOIS. Will Co.: along Joliet Rd. (old US Hwy 66), opposite entrance to Traders Corner Picnic Area of Veterans Woods Forest Preserve, 0.4 mi. NE of its junction with State Hwy 53, single plant in roadside thicket, 18 Aug 1990, T G. Lammers 7428 (F, TEX). Though both parental species are common in prairies of the region, this is the first report of their hybrid. Silphium integrifolium was quite common at the site, while S. terebinthinaceum was represented by just a single multi-stemmed clump. Near the latter was a similar clump of the putative hybrid. This hypothesis of hybridity was based upon morophological intermediacy. For example, the suspected hybrid had sparsely leafy stems averaging 1.5 m tall, which are clearly intermediate between the more densely leafy stems of S. integrifolium, which averaged 1.4 m tall, and the scapose stems of S. terebinthinaceum, which averaged 2.5 m tall. Similarly, the alleged hybrid had winged petioles with a pair of large stipule-like flanges at base; these seem a compromise between the sessile clasping leaves of S. integrifolium and the petiolate leaves of S. terebinthinaceum. Associated with the hybrid and its parents in the thicket were Asclepias syriaca L., Aster ericoides L., A. novae-angliae L., Cirsium altissimum (L.) Spreng., Cornus racemosa Lam., Eupatorium rugosum Houtt., E. serotinum Michx., Helianthus grosseserratus M. Martens, Oenothera biennis L., Parthenocissus quibquefolius (L.) Planch., Rosa carolina L., Solidago canadensis L., Vitis riparia Michx. Viburnum lantana L. (Caprifoliaceae) Wayfaring Tree ILLINOIS. Will Co.: Bolingbrook, along S bank of Lily Cache Creek, just E of the Schmidt Rd. culvert, weedy disturbed floodplain field, 2 May 1998, T G. Lammers 10627 (BRIT, F, MU, NA). Native of Eurasia, frequently naturalized in the region. LITERATURE CITED Swink, F., & G. Wilhelm. 1994. Plants of the Chicago Region, ed. 4. Indiana Academy of Science, Indianapolis.