Description

Taxonomy

Kingdom	Phylum	Class	Order	Family	Genus
Plantae	Magnoliophyta	Magnoliopsida	Polygonales	Polygonaceae	Polygonum

Synonyms

Polygonum caespitosum; Polygonum cespitosum var. longisetum

Invasion History

Chesapeake Bay Status

First Record	Population	Range	Introduction	Residency	Source Region	Native Region	Vectors
1931	Established	Expanding	Introduced	Boundary Resident	East Asia	East Asia	Agriculture(Packing Material)

History of Spread

Polygonum cespitosum (Asian Ladies-Thumb) is a rice paddy weed in southeast Asia, found from China to Sumatra and the Phillipines (Paterson 2000). Fernald (1935) suggested rice straw, used as a packing material, as a potential route for the import of this species and other Asian plants to North America. This plant spread south to MD and DE by 1950 (Fernald 1950), AL and AR by the 1980's, and west to Omaha NB by 1986 (Kochman 1991). Polygonum cespitosum reached the Hudson Basin by 1936 and the Great Lakes region by 1951 (Mills et al. 1993; Mills et al. 1997). Currently, it is known from ME and VT to FL, and west to MN, NE, and AZ (Natural Resources Conservation Service 1998; Paterson 2000).

Polygonum cespitosum reached Washington D.C. by 1931 (Blake 1932), and now is widespread in VA (Harvill et al. 1992), and is 'becoming common' in MD (Brown and Brown 1984). However, the only specific estuarine record found so far is from the upper Patuxent estuary (Krauss et al. 1971). However, this plant is abundant on the upper regions of tidal marshes in the Potomac River at Dyke Marsh and Theodore Roosevelt Island, and occurred in the intertidal zones of bridge embankments on the Pocomoke River MD (Fofonoff, personal observations).

History References - Brown and Brown 1984; Fernald 1935; Fernald 1950; Harvill et al. 1992; Kochman 1991; Krauss et al. 1971; Mills et al. 1993; Mills et al. 1997; Natural Resources Conservation Service 1998; Paterson 2000

Invasion Comments

Invasion Status- This species is listed as 'native”, according to the USDA 'Plants' Database (Natural Resoruces Conservation Service 2002), but exotic in every other source which we have consulted.

Ecology

Environmental Tolerances

	For Survival		For Reproduction
	Minimum	Maximum	Minimum	Maximum
Temperature (ºC)	-23.0
Salinity (‰)	0.0		0.0
Oxygen
pH
	Salinity Range	fresh-oligo

Age and Growth

	Male	Female
Minimum Adult Size (mm)
Typical Adult Size (mm)
Maximum Adult Size (mm)
Maximum Longevity (yrs)
Typical Longevity (yrs

Reproduction

	Start	Peak	End
Reproductive Season
Typical Number of Young Per Reproductive Event
Sexuality Mode(s)
Mode(s) of Asexual Reproduction
Fertilization Type(s)
More than One Reproduction Event per Year
Reproductive Startegy
Egg/Seed Form

Impacts

Economic Impacts in Chesapeake Bay

Polygonum cespitosum (Asian Ladies-Thumb) is increasing in abundance as a upland weed in the Chesapeake Bay watershed (Brown and Brown 1984; Harvill et al. 1992) and is now common to abundant in the upper intertidal zone of some tidal fresh wetlands in the Bay (Fofonoff, personal observations; Tiner and Burke 1995). However, no economic impacts have been reported.

References- Brown and Brown 1984; Fofonoff, personal observations; Harvill et al. 1992; Tiner and Burke 1995; Virginia Department of Conservation and Recreation 1999

Economic Impacts Outside of Chesapeake Bay

Polygonum cespitosum (Asian Ladies-Thumb) is increasing rapidly in range and abundance in eastern North America (Kochman 1991; Paterson 2000). It is a rice paddy weed in Asia (Kochman 1991), but economic impacts in the United States have not been reported, to our knowledge.

References- Paterson 2000

Ecological Impacts on Chesapeake Native Species

Polygonum cespitosum (Asian Ladies-Thumb) is increasing in abundance as an upland weed in the Chesapeake Bay watershed (Brown and Brown 1984; Harvill et al. 1992) and is now common to abundant in the upper intertidal zone of some tidal fresh wetlands in the Bay (Fofonoff, personal observations; Tiner and Burke 1995), but the extent to which it has displaced native plants is unknown. This plant was considered to be moderately invasive in VA (Virginia Department of Conservation and Recreation 1999).

References- Brown and Brown 1984; Fofonoff, personal observations; Harvill et al. 1992; Tiner and Burke 1995; Virginia Department of Conservation and Recreation 1999

Ecological Impacts on Other Chesapeake Non-Native Species

Polygonum cespitosum (Asian Ladies-Thumb) is increasing in abundance as a upland weed in the Chesapeake Bay watershed (Brown and Brown 1984; Harvill et al. 1992) and is now common to abundant in the upper intertidal zone of some tidal fresh wetlands in the Bay (Fofonoff, personal observations; Tiner and Burke 1995), but the extent to which it has affected other exotic biota is unknown.

References- Brown and Brown 1984; Fofonoff, personal observations; Harvill et al. 1992; Tiner and Burke 1995

References

10/14/2009 Weevil helps control invasive plant in Hyattsville. http://www.anacostiaws.org/news/blogs/weevil-helps-control-invasive-plant-hyattsville

Blake, S. F. (1932) Polygonum caespitosum var. longisetum in the United States, Rhodora 34: 146-147

Brown, Melvin L.; Brown, Russell G. (1984) Herbaceous Plants of Maryland, , College Park. Pp.

Fernald, M. L. (1935) Midsummer vascular plants of southeastern Virginia, Rhodora 37: 378-454

Fernald, Merritt L. (1950) Gray's Manual of Botany, In: (Eds.) . , New York. Pp.

Gleason, Henry A. (1963) The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada, In: (Eds.) . , New York. Pp.

Gleason, Henry A.; Cronquist, Arthur (1991) Manual of vascular plants of northeastern United States and adjacent Canada, In: (Eds.) . , Bronx, New York. Pp.

Harvill, A. M., Jr.; Bradley, T. R.; Stevens, C. E.; Weiboldt, T.F.; Ware, D.E.; Ogle, D. W. (1986) Atlas of the Virginia Flora, , Farmville, VA. Pp.

Harvill, A. M.; Bradley, Ted R.; Stevens, Charles E.; Wieboldt, Thomas F.; Ware, Donna M. E.; Ogle, Douglas W.; Ramsey, Gwynn W.; Fleming, Gary P. (1992) Atlas of the Virginia Flora, , Burkeville, VA. Pp.

Kartesz, John T. (1994) A synonymized checklist of the vascular flora of the United States, Canada, and Greenland., In: (Eds.) . , Portland OR. Pp.

Kochman, A. (1991) Polygonum caespitosum: an Asian invader in the wetland flora of the eastern United States, Ohio Journal of Science 91: 28

Krauss, R.W.; Brown, R. G.; Rappleye, R. D.; Owens, A. B.; Shearer, C.; Hsiao, E.; Reveal, J. (1971) Checklist of plant species occurring within the hightide limits of the Chesapeake Bay, and its tributaries., , College Park, Maryland. Pp.

Mills, Edward L.; Leach, Joseph H.; Carlton, James T.; Secor, Carol L. (1993) Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions., Journal of Great Lakes Research 19: 1-54

Mills, Edward L.; Scheuerell, Mark D.; Carlton, James T.; Strayer, David (1997) Biological invasions in the Hudson River: an inventory and historical analysis., New York State Museum Circular 57: 1-51

1997-2024 USDA PLANTS Database.. Onine databse

Paterson, Anne K. (2000) Range expansion of Polygonum caespitosum var. longisetum in the United States, Bartonia 60: 57-69

Resource Management Inc. (1993) National list of plant species that occur in wetlands., , Minneapolis.. Pp.

Tiner, Ralph W., Jr.; Burke, David G. (1995) Wetlands of Maryland, , Newton Corner, MA. Pp.

1999 Invasive Alien Plant Species of Virginia. http://www.state.va.us/~dcr/dnh/invlist.htm