Six new species to the flora of Wisconsin, and where to find more
Emmet J. Judziewicz and John Zaborsky
Submitted 29 August 2012
With global warming really beginning to kick in, we can expect to see more heat-tolerant invasive plants to appear in Wisconsin. Such has been the case during the first ten years of the 21st century, and in particular during 2012. Here are some new records for our state, in chronological order. Click here for PDF that includes photographs.
Fairgrounds grass (Sclerochloa dura)
This Eurasian grass, tolerant or heat, salt, and trampling, was first collected in Wisconsin by University of Michigan Botanist Richard K. Rabeler in 2001, in Rock and Walworth Counties: It had been collected many times in the Chicago regions since 1992 and it was only a matter of time until it reached Wisconsin. As the common name indicates, it often appears first at county and state fairgrounds: http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=SCLDUR
Plains bluegrass (Poa arida)
This is a salt- and drought-tolerant western U.S. species that was first collected in Wisconsin in heavily salted ditches along I-94 in Kenosha and Racine Counties by Illinois botanist Gerould Wilhelm in 2008. Wilhelm had previously detected it frequently, starting in 1991, along interstate highways in the Chicago Region. It is an early-flowering bluegrass (like Poa annua), but has a pale, ghostly color. Like Fairgounds grass, it will probably move north in Wisconsin in the coming years. http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=POAARI
This Eurasian member of the sunflower or composite family (Asteraceae) was first collected along the active, north-south running railroad along the east bank of the Mississippi River a few miles south of Cassville, Grant County, by Neil Harriman and Tom Eddy. Neil identified it at the University of Wisconsin-Oshkosh herbarium. Small hawksbeard is present in Illinois and Indiana but is rare in both states. The Cassville railroad site produced two other state records in 2012
Windmill grass (Chloris verticillata)
Windmill grass (Chloris verticillata), a native of the southern U.S. that has recently become weedy in northern Illinois, was first collected as a weed at Muscoda, Grant County, on 15 August 2012 by Emmet Judziewicz, along a paved footpath in park on the banks of the Wisconsin River. It looks like a pale green, prickly crabgrass due to its finger-like spikes of awned spikelets.
Small white morning glory (Ipomaea lacunosa)
Small white morning glory (Ipomaea lacunosa), a southern U.S. species, was first collected at the “Cassville railroad site” in Grant County on 19 August 2012 by John Zaborsky and Emmet Judziewicz, and photographed (below) and identified by Zaborsky. It has heart-shaped leaves, and, as its common name suggests, small white flowers. This species is native in the northern ¾ of Illinois, the Wisconsin collection representing a northern range extension of about 100 miles. http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=IPOLAC
Five-hook bassia (Bassia hyssopifolia)
On the same morning, John and I also found this Eurasian member of the amaranth family (Amaranth family, including the old Chenopodiaceae) in the same locality as small hawksbeard and small white morning-glory. It was locally common and almost formed a sterile 0.75 m “hedge” in the railroad ditch in places; the flower buds were just beginning to appear. The USDA web site has this Eurasian weed as rare in South Dakota, Iowa, and Kentucky in the Midwest, commoner as a weed in the western U.S.
Where we might expect to find additional new Wisconsin plant records
Clearly, more heat- and drought-tolerant Eurasian and southern and western North American species may be expected to be found in Wisconsin, especially in disturbed areas such as heavily salted highway margins and railroad rights-of-way in the far south near the Illinois border. A week spent carefully botanizing such habitats would be productive, especially later in the summer when these species tend to bloom. The Cassville railroad site had characteristics that proved conducive to these new invaders: heavy train traffic, on a south to north route, apparently non-herbicided margins in most places, and a ditch and small embankment on the outside of a curve, where gravity would be expected to dislodge hitchhiking seeds. Result: Three state records, and we did not survey it completely…