Page  196 ï~~196 THE MICHIGAN BOTANIST Vol. 44 NEW RECORDS FOR RUELLIA HUMILIS NUTTALL (ACANTHACEAE) IN WISCONSIN Thomas L. Eddy 426 Walker Avenue Green Lake, WI 54941 The genus Ruellia Linnaeus is represented by four species in northeastern U.S. and adjacent Canada (Gleason and Cronquist 1991). Of these, Ruellia humilis Nuttall is reported to occur in 25 states in the U.S. The plant is listed on state threatened (T) and endangered (E) species lists in Maryland (E), Michigan (T), North Carolina (T) and Pennsylvania (E). In Wisconsin R. humilis is endangered (WDNR, 2005), known from six counties in the two southernmost-tiers of the state (Crawford, Dane, Grant, Portage, Rock, and Walworth) (Wisflora, 2005). Two recent collections of R. humilis in Outagamie and Winnebago counties have extended the known range distribution to northeastern Wisconsin. Ruellia humilis is a perennial forb that goes by numerous common names: fringe-leaf ruellia, hairy ruellia, hairy wild petunia, and wild petunia. Two varieties of R. humilis are recognized: var. calvescens Fern. of the Appalachian region and var. humilis (subject of this report), which is the common and widespread variety with densely hairy internodes, calyx lobes, and leaf veins and margins. Ruellia humilis var. humilis inhabits prairies and dry upland woods, ranging from Pennsylvania to northern Indiana, southeastern Minnesota, Nebraska, south to western North Carolina, Alabama, and Texas (Gleason & Cronquist, 1991). In Wisconsin R. humilis is quite rare. It flowers near the end of June to midSeptember and fruits from the end of July to September. The plant occurs on dry and dry-mesic prairies, but has been documented more often on disturbed grasslands within railroad right-of-ways, river terraces, and bluffs. Although not a usual occurrence, R. humilis was collected from a weedy ditch as an escape in Middleton, Dane County, in 1995 (Cochrane and Iltis 2000). With seed readily available by commercial plant nurseries, R. humilis is occasionally propagated during native restoration efforts and in prairie flower gardens. The two records reported here are most unlikely to be escapes from cultivation. The first Wisconsin record of Ruellia humilis is without a specific date but it was collected on or between 1849 and 1862 (Cochrane and Iltis 2000). The next earliest specimen was recorded from Rock County in 1875, while the remainder of dated vouchers are specimens collected in 1921, 1931, 1940, 1987, 1990, 1992, 1993, 1997, and 1998 (Wisflora, 2005). On 12 July 2003, Ruellia humilis (OSH, accession number 106308) was collected from Outagamie County along a roadside ditch off State Highway 55 near Kaukauna. According to the specimen label, the plant was in a "tall grass prairie... the collector supposes the plant is native there."

Page  197 ï~~2005 THE MICHIGAN BOTANIST 197 Two years later on 30 August 2005, R. humilis was documented in Winnebago County. Like the specimen in Outagamie County, the Winnebago County voucher (OSH accession number 112304) was collected on a prairie remnant within the right-of-way of U.S. 45 (state route 110 on maps more than 2 years old). According to the voucher label, the dry-mesic remnant occurs on top of a limestone (dolomite) outcrop that "is perched above the ditch, such that mowing machines and snowplows cannot reach it." Associates of Ruellia humilis at the Winnebago County site include: Andropogon gerardii, Asclepias verticillata, Aster ericoides, A. oolentangiensis, Bouteloua curtipendula, Dalea purpureum, Euphorbia corollata, Geum triflorum, Helianthus grosseserratus, H. occidentalis, Isanthus brachiatus, Liatris aspera, Monarda fistulosa, Panicum virgatum, Ratibida pinnata, Rhus glabra, Rosa blanda, Schizachyrium scoparium, Silphium integrifolium (Winnebago County record), S. laciniatum, S. terebinthinaceum, Solidago rigida and Verbena simplex, this last species a state Special Concern species (WDNR, 2005). One noteworthy species among the associates of Ruellia humilis is Coreopsis tripteris, a new record for Wisconsin that was first collected in 2004 (Wisflora, 2005; Eddy 2005). Since this remnant is situated within the highway right-ofway, the creation of a GIS layer that documents R. humilis and associates can assist local and state highway and planning departments to easily locate and then protect this native plant refugium, as well as other roadside remnants, during the planning phase of future highway projects. LITERATURE CITED Cochrane, T. S. & H. H. Iltis. 2000. Atlas of the Wisconsin Prairie and Savanna Flora. Department of Natural Resources Technical Bulletin 191. Madison, WI. Eddy, T. L. 2005. Coreopsis tripteris L. (Asteraceae) in Wisconsin. Michigan Botanist 44(3): 159-165. Gleason, H. A. & A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. New York Botanical Garden, Bronx, NY. Wisconsin Department of Natural Resources. 2004. The natural heritage inventory working list: rare vascular plants. Retrieved 28 September 2005, from Wisconsin Natural Heritage Inventory Web site: Wisflora: Wisconsin vascular plant species. 2005. Retrieved 28 September 2005, from Wisflora: Wisconsin Vascular Plant Species Web site: