From Plant Press, Vol. 19, No. 4, October 2016.
By Robert J. Soreng & R.H. Simmons
While botanizing in Garrett County, Maryland, early this summer Rod Simmons, a Smithsonian Research Collaborator, and Rob Soreng spotted and collected fowl bluegrass, Poa palustris, a grass thought to be rarely collected in the state. One location was along the river in Casselman River Bridge State Park, and the other location was in Swallow Falls State Park along the Youghiogheny River, where it was associated with Trautvetteria caroliniensis, Avenella flexuosa, Rhododendron arborescens, R. maximum, and Tsuga canadensis. Voucher specimens from both collections (9322, 9321) are at the U.S. National Herbarium (US) and the Maryland Department of Natural Resources Herbarium (TAWES), a duplicate of specimen 9322 is at University of Maryland, Norton – Brown Herbarium (MARY), and specimen 9321 is at City of Alexandria Herbarium (AVCH).
Poa palustris was previously reported in Maryland from a few old collections, collected in the state some 60 years ago—Prince George’s County, Suitland Bog, in 1965 (F.G. Meyer 9233, NA), and Baltimore County, Soldiers Delight, in 1972 (F.J. Monteferrante 076, BALT). We redetermined these as Poa pratensis L. subsp. pratensis and Glyceria canadensis or laxa, respectively from photos kindly provided by Joan Feely (NA) and David Hearn (BALT). The earliest collection from our area may be from D.C., by E.S. Steele s.n., 22 July 1896 (US-DC) (Steele was collecting in the vicinity of Brookland and Terra Cotta [Fort Totten] on that date). Reports from Howard and Washington Counties by M.L. Brown and R.G. Brown (Herbaceous Plants of Maryland; 1984) and repeated by E.E. Terrell and P.M. Peterson (J. Bot. Res. Inst. Texas 3: 905-919; 2009) are also based on erroneous identifications (at MARY – photos kindly provided by John Hall).
Before these new discoveries in Maryland, Poa palustris was ranked SH (State Historical - Possibly Extirpated in Maryland), based on the three old voucher specimens cited above. Now Maryland State Botanist Chris Frye (and Maryland Natural Heritage team) will likely list it as S1 (Critically Imperiled in Maryland). The species mainly occurs in boreal wetlands and is widespread across the United States, southern Canada, and across Eurasia. It is considered native in North America, but is also introduced for stabilization of riparian habitats, mainly or only in western North America. There are a few cultivars originating from northwestern Europe.
Soreng has also collected this species in the Dolly Sods (7464) and Canaan Valley of West Virginia (7459) (in 2004), and Bath County, Virginia (3247, in 1987). It is known from at least eight counties in the mountains of Virginia, three in North Carolina, and one in Tennessee. He and Simmons interpret these central and other more southern Appalachian occurrences as relicts from glacial periods.