ELEMENT STEWARDSHIP ABSTRACT FOR POLYGONUM GLAUCUM November 29, 1990 Stewardship Abstract No.: 014 By Alfred E. Schuyler For: State of New Jersey Department of Environmental Protection and Energy Division of Parks and Forestry Office of Natural Lands Management CN 404 Trenton, New Jersey 08625 Element Stewardship Abstract Element Stewardship Abstracts (ESA's) are prepared to provide land managers and other conservation workers with current biological and management related information on those species and natural ecosystems that are most important to protect or for which control is most needed. The abstracts organize and summarize data from numerous sources, including the literature and from researchers and managers actively working with the species or ecosystem. The ESA format was originally developed by The Nature Conservancy as a starting point for the stewardship of the many species and ecosystems, or elements, protected by the Conservancy. The New Jersey Office of Natural Lands Management is developing ESA's for those elements that are of particular importance as components of the biota of the state. This includes globally rare plant species that are also listed on New Jersey's official Endangered Plant Species List. The ESA serves several important functions. It helps to identify information gaps and target future research efforts. It provides a standard format for highlighting specific information about a species or community including its management needs. It also allows information to be readily communicated among various preserves, state offices, regional centers, natural heritage programs and private organizations. The ESA is a dynamic document that is continuously updated as new information becomes available. Users are encouraged to contribute their information to the abstract. This sharing of information will benefit all land managers by ensuring the availability of up-to-date information on management techniques and knowledgeable contacts. Please contact the Office of Natural Lands Management for an ESA publication list. It will contain the date of the latest revision to each ESA. Please refer to the abstract number when ordering ESA's. The abstract is a compilation of available information and is not an endorsement of particular practices or products. Element Name: POLYGONUM GLAUCUM Nutt. (Polygonaceae) Element Code: PDPGNOL120 Preparer: Alfred E. Schuyler Common Name: Sea-beach Knotweed Description: Habit: small annual or perennial (?) herb with prostrate to erect branching stems having alternate whitish leaves with axillary clusters of small inconspicuous flowers. Stem: prostrate to erect firm branching stems up to 0.3 m long. Leaves: alternate entire narrowly elliptic whitish leaves up to 3 cm long, crowded along branches, the upper much reduced. Axillary silvery sheathing stipules up to 10 mm long. Inflorescence: small clusters of 1-3 flowers in axils of reduced leaves, pedicels included in axillary sheaths. Flowers: 5 sepals broadly obovate, white or pink, slightly spreading, up to 4 mm long. Petals lacking. Stamens 8, enclosed by sepals. Pistil with 3 styles up to 0.4 mm long. Fruits: 3-angled achenes, ovate with acute tips, shiny, brown to blackish, protruding beyond sepals, up to 4 mm long. Chromosomes: Lo"ve reported (1956) 2n=40 and considered the plants to be tetraploids. Distinctions from Related Species: Polygonum raii, which occurs in similar habitats in eastern Canada and northwestern Europe, has less whitened foliage, shorter sheathing stipules (up to 8 mm long), and longer achenes (up to 5.3 mm long). The European P. maritimum has longer stipules (up to 18 mm long) and longer achenes (up to 5 mm long). Habitat: Polygonum glaucum occurs along the Atlantic Coast from Massachusetts to Georgia (Fernald, 1950; Mitchell and Dean, 1978). It grows on sandy seabeaches, shores of coastal ponds, margins of saline marshes, and dune-hollows (Fernald, 1950; Harshberger, 1900; Mitchell and Dean, 1978). In Massachusetts, Sorrie (1987) reports, "It prefers washover areas near saltponds, beaches with active sand deposition, and sandspits." On Assateague Island in Maryland and Virginia, Hill (1986) reported that P. glaucum was infrequent to rare in washes, disturbed sands, and dunegrass swales. Farther south on Wallops Island, Virginia, Klotz (1986) gave its habitat as foredunes. In South Carolina, Coker (1905) reported finding it on dunes on the Isle of Palms where the plants were associated with Cenchrus tribuloides, Physalis pubescens, Phytolacca americana, Sabal palmetto, Salsola kali, and Yucca alnifolia. In New Jersey P. glaucum is known from about 15 scattered sites near the Atlantic Ocean between Middlesex and Cape May counties, and one from Camden where it was collected on ballast in 1897 (NJNHP, 1989a). There also is a report of it growing on fill along the New Jersey Turnpike in Middlesex County (Snyder, 1989) in an area that probably was in or adjacent to tidal wetlands. Most occurrences are on sandy beaches where the plants generally occur above the limit of the tide (NJNHP, 1989a; Snyder, 1989). On Island Beach, Snyder (NJNHP, 1989a) reported that it was growing with Ammophila breviligulata and Chamaesyce polygonifolia. Biology/Ecology: Flowering and fruiting takes place over a long period from May to November (Fernald, 1950; Radford et al., 1968). The flowers probably are self-pollinated to a large extent. Coulter (1892) reported that he found cleistogamous flowers in numerous species of Polygonum. In the related Polygonum aviculare, Knuth (1909) reported that the flowers are "almost limited to automatic self- pollination, which is very effective, as almost all flowers set fruits." However, Knudson (1909) reported that when the "flowers are visited by insects, either self- or cross-pollination may be effected with equal facility." Seeds of different species of Polygonum are dormant at maturity and after-ripen at low temperatures (Justice, 1941). In his study of seed dormancy, Justice (1941) found that most seeds failed to after-ripen completely if not chilled in a moist medium. The occurrence of P. glaucum in washes and disturbed sands (Hill, 1986; Sorrie, 1987) indicates that it is a pioneer species of unstable habitats. It also has few competitors in these sparsely vegetated habitats where it often grows on bare sand (Coker, 1905; NJNHP, 1989a). Sorrie (1987) reports that it is an aggressive colonizer in such habitats. Achenes of Polygonum are eaten by various kinds of birds (Martin et al., 1951), which probably also act as agents of dispersal. Determination of Element Occurrence (EO) Quality: Polygonum glaucum "appears to be maintaining adequate population levels" in Massachusetts (Sorrie, 1987) and is still locally frequent on the shores of Long Island (Snyder, 1989). It has not been recently observed in Delaware and is known only from a few scattered localities in Maryland and Virginia (Hirst, 1990). In the Carolinas, there are few recent collections although the plants have not been extensively searched (Schafale, pers. comm., 1990) and may have been overlooked (Gaddy and Rayner, 1980). In New Jersey, only three plants were confirmed extant after much searching in 1987 (Snyder, 1989). These plants occurred on beaches at two sites where they are vulnerable to human disturbance. Two plants were in an area that receives considerable foot traffic and the other plant was growing between tire ruts made by off road vehicles. Plants were flowering and fruiting at both sites. Threats: Snyder (1989) reports that P. glaucum is "especially vulnerable to off road vehicle traffic, mechanical beach raking, and beach reclamation projects." If natural disturbances are not allowed to occur, there will be fewer available habitats for P. glaucum. Land Protection Specifications: Beaches and dunes where natural washes and depositions occur should be protected. Tracts of land have to be large enough to allow these disturbances to occur in more than one place so the plants can have access to new pioneer habitats as older habitats are stabilized. Recovery Potential: As pioneer species of sandy nutrient-poor substrates, recovery at severely damaged sites probably would be a slow process. Reduction of available habitat and substantial population gaps make P. glaucum more dependent on a local seed source which may not be available at such sites. In some situations, however, it apparently is an aggressive colonizer (Sorrie, 1987). At sites where plants still exist, recovery may therefore be high if the proper pioneer habitat conditions are restored. Biological Monitoring Needs: Population sizes should be monitored at present sites and searches should be made for plants at new sites. Biological Monitoring Procedures: Search new sites where habitat conditions are similar to those at known sites. Make annual visits to known sites and record number of plants present. Biological Monitoring Programs: David Snyder probably has the most knowledge concerning the New Jersey occurrences of P. glaucum and has contact with others who are knowledgeable. Management Needs: At sites where P. glaucum is still extant, adjacent disturbed areas are needed to provide additional habitats for colonization. These should be unstable habitats created by washes and sand deposition. If such habitats are not being created naturally, management should provide the necessary disturbances. Management Procedures: Making beaches more unstable to accommodate rare plants will arouse some controversy. Management should concentrate on local areas and proceed with a minimal level of disturbance. Small groups of people working with shovels are preferable to using heavy duty equipment such as bulldozers. Summary of Stewardship Needs: Polygonum glaucum occurs along the Atlantic Coast from Massachusetts to Georgia on sandy beaches, dunes, dune-hollows, pond shores, and margins of saline marshes. It is a pioneer species of unstable habitats created by washovers and active sand deposition. It is rare throughout most of its range and in New Jersey it has been found only at two sites in recent time. The plants are threatened by off road vehicles, mechanical beach raking, and beach reclamation projects. Tracts of land should be protected that are large enough to allow the plants to have access to new pioneer habitats. Recovery potential is probably low because of nutrient-poor substrates, habitat reduction, and population gaps although the species may be an "aggressive colonizer" under optimum conditions. Population sizes need careful monitoring and searches should be conducted at new sites. At sites where P. glaucum is still extant, management is needed to provide additional unstable habitats if natural disturbances are not sufficient to create them. Bibliography for Polygonum glaucum nutt: Coker, W.C. 1905. Observations on the Flora of the Isle of Palms, Charleston, S.C. Torreya 5(8): 135-145. Fernald, M.L. 1913. Some North American Relatives of Polygonum maritimum. Rhodora 15: 68-73. Fernald, M.L. 1950. Gray's Manual of Botany. 8th ed. American Book Co., New York. lxiv + 1632 pp. Fogg, J.M., Jr. 1930. The Flora of the Elizabeth Islands, Massachusetts. Rhodora 32: 119-132, 147-161, 167-180, 208-221, 226-258, 263-281. Gaddy, L.L. & D.A. Rayner. 1980. Rare or Overlooked ? Recent Plant Collections from the Coastal Plain of South Carolina. Castanea 45: 181-184. Gleason, H.A. 1952. The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada. The New York Botanical Garden, New York. 3 v. Harshberger, J.W. 1900. An Ecological Study of the New Jersey Strand Flora. Proc. Acad. Nat. Sci. Philadelphia 52(3): 623-671. Hill, S.R. 1986. An Annotated Checklist of the Vascular Flora of Assateague Island (Maryland and Virginia). Castanea 51(4): 265- 305. Hirst, F.C. 1990. Stockton, MD, personal communication. Klotz, L. H. 1986. The Vascular Flora of Wallops Island and Wallops Mainland, Virginia. Castanea 51(4): 306-326. Knuth, P. 1909. Handbook of Flower Pollination, Vol. III, Goodenovieae to Cycadeae. Translated by J.R. Ainsworth Davis. Henry Frowde, Publisher to the University of Oxford, London. Lo"ve, A. & D. Lo"ve. 1956. Chromosomes and Taxonomy of Eastern North American Polygonum. Canad. J. Bot. 34(4): 501-521. Martin, A.C., H.S. Zim & A.L. Nelson. 1951. American Wildlife and Plants. McGraw-Hill Book Co., Inc., New York. Mertens, T.R. & P.H. Raven. 1965. Taxonomy of Polygonum, Section Polygonum (Avicularia) in North America. Madron~o 18(3): 85-92. Mitchell, R.S. & J.K. Dean. 1978. Polygonaceae (Buckwheat Family) of New York State. New York State Mus. Bull. No. 431, 81 pp. Mitchell, R.S. & C.J. Sheviak. 1981. Rare Plants of New York State. New York State Mus. Bull. No. 445, viii + 96 pp. Mitchell, R.S., C.J. Sheviak & J.K. Dean. 1980. Rare and Endangered Vascular Plant Species in New York State. U. S. Fish and Wildlife Service, Newton Corner. 38 pp. NJNHP. 1989a. Element Occurrence Summaries. New Jersey Natural Heritage Program, Trenton. NJNHP. 1989b. State Ranking Forms. New Jersey Natural Heritage Program, Trenton. Olney, S.T. 1874. Block Island Rarities. Bull. Torrey Bot. Club 5(9): 38. Radford, A.E., H.E. Ahles & C.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The University of North Carolina Press, Chapel Hill. lxi + 1833 pp. Robinson, B.L. 1902. The New England Polygonums of the Section Avicularia. Rhodora 4(40): 65-73. Schafale, M.P. 1990. North Carolina Natural Heritage, Raleigh, NC, personal communication. Seymour, F.C. 1969. The Flora of New England. The Charles E. Tuttle Co., Publishers, Rutland. xvi + 596 pp. Small, J.K. 1892. A Preliminary List of American Species of Polygonum. Bull. Torrey Bot. Club 19: 351-370. Snyder, D.B. 1989. Notes on Some Recently Rediscovered New Jersey Plant Species. Bartonia No. 55: 40-46. Sorrie, B.A. 1987. Notes on the Rare Flora of Massachusetts. Rhodora 89: 113-196.