ELEMENT STEWARDSHIP ABSTRACT FOR PANICUM WRIGHTIANUM November 29, 1990 Stewardship Abstract No.: 011 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: PANICUM WRIGHTIANUM Scribn. (Poaceae) Element Code: PMPOA240Z0 Preparer: Alfred E. Schuyler Common Name: Wright's Witchgrass Description: Habit: perennial tufted herb with weak ascending or spreading stems having narrow sheathing leaves and both terminal and axillary branched inflorescences with minute flowers. Stem: culms in small tufts, weak, ascending or spreading, up to 0.6 m tall, becoming branched as season progresses, with minute hairs below middle. Leaves: blades of leaves along stems narrowly ovate, up to 4 cm long and 6 mm wide, with soft hairs on lower surface. Sheaths shorter than internodes. Ligule a tuft of hairs 2-3 mm long. Basal leaves shorter than those along stems and persisting as winter rosettes. Inflorescence: early primary panicles elliptic to ovate, up to 6 cm long, with minute hairs on axis. Forking ascending branches bearing minute long-stalked spikelets. Later axillary panicles smaller than early primary panicles. Spikelets: elliptic or ovate, blunt, up to 1.1 mm long, with minute hairs, first glume about 1/4 of spikelet length. Overwintering Characteristics: rosettes of short green leaves persist throughout winter. Chromosomes: Brown (1948) reported 2n=18 for plants collected in the southeastern United States. He also reported this number for related species. Distinctions from Related Species: Panicum wrightianum closely resembles species in the P. acuminatum (lanuginosum) complex and is considered by some (Gould and Clark, 1978) to be conspecific with P. acuminatum. It differs from these species by having shorter spikelets: 0.8-1.1 mm long vs. 1.2 mm or more long. Some botanists place P. wrightianum in the genus Dichanthelium (Gould and Clark, 1978; Freckmann, 1981). Others (Webster, 1988) continue to treat Dichanthelium as a subgenus of Panicum. Habitat: The range of P. wrightianum extends along the Coastal Plain from Massachusetts to Florida and west to Texas (Gould and Clark, 1978). It also occurs in Cuba and Belize (Freckmann, 1981). It grows on pond shores, in or around wet depressions, and around pools in cypress swamps (Fernald, 1943; Radford et al. 1968; Sinnott, 1912). The substrate is sandy, peaty or muddy (Fernald, 1950; Gould and Clark, 1978). In Massachusetts, Sorrie (1987) reported that it is "Frequent on sandy-peaty shores of Coastal Plain ponds, often in company with Eleocharis melanocarpa, Fuirena pumila, Drosera filiformis and Sabatia kennedyana." In Virginia, Fernald (1937, 1943) reported it from wet depressions and pond shores on sandy or peaty substrates. Associates included Eleocharis microcarpa, Hedyotis boscii, Hydrolea quadrivalvis, Hypericum denticulatum, Leersia hexandra, Panicum hemitomon, Rhynchospora caduca, Rhynchospora perplexa, Sabatia campanulata, and Viola lanceolata. In New Jersey, P. wrightianum is known from the southern part of the Pine Barrens and adjacent portions of the Coastal Plain in Atlantic, Camden, Cape May, Cumberland, and Salem counties. The habitat usually is dry pond bottoms or bogs (NJNHP, 1989a; ANSP, 1990) on Pocomoke Sandy Loam that are periodically wet or dry (Stasz, pers. comm., 1990). Associated species include Amphicarpum purshii, Eleocharis melanocarpa, Hypericum gentianoides, Muhlenbergia torreyana, Scleria reticularis, and Viola lanceolata (Stasz, pers. comm., 1990). Biology/Ecology: Panicum wrightianum flowers from June to November. As with other species in subgenus Dichanthelium, reproduction is presumed to be predominantly autogamous with sporadic outcrossing (Freckmann, 1981). Panicum wrightianum is more conspicuous some years than others (Fernald, 1939) and is more frequently found when seasons are dryer than usual (Stasz, pers. comm., 1990). The habitats are early successional ones where competitors are eliminated by the unstable water regime. Panicum wrightianum is known from habitats disturbed by humans. Fernald (1937) reported it from "wet woodroads" and shores of millponds in Virginia. At Grassy Pond in Atlantic County, New Jersey, P. Wrightianum persisted after the site was ditched in the 1940's (Stasz, pers. comm., 1990). The presence of P. Wrightianum in dry years and its absence in wet years suggest that its seeds persist as a seed bank and germinate when conditions are favorable for survival. However, it is uncertain how much reproduction occurs from perennial rosettes that remain sterile until conditions are favorable for culm production. Determination of Element Occurrence (EO) Quality: At most known New Jersey sites, the EO quality probably is good although this is difficult to judge because substantial fluctuation in population size is an expected condition of this species. Threats: The major threat to P. wrightianum is stabilization of its water regime. Water level fluctuation is essential to maintain the habitat as early successional with few competitors. Habitat destruction from development is a threat to those sites near Atlantic City. Land Protection Specifications: As long as nothing is done to alter fluctuating water regimes, P. wrightianum should not need further protection. Recovery Potential: Recovery potential in severely degraded habitats is probably low. Early successional habitats usually are nutrient poor and recolonization by pioneer species is a slow process. Substantial population gaps make P. wrightianum dependent on a seed bank or perennial rosettes to persist at a given site. Recovery potential from some human disturbances is probably high when degradation is not severe and the water regime is maintained. Biological Monitoring Needs: Population sizes at selected sites should be monitored. More information is needed on the present distribution of this species in New Jersey and on year-to-year fluctuations in population size. Biological Monitoring Procedures: Record numbers of culms and rosettes at selected sites so year- to-year comparisons can be made. Searches should be made to relocate plants at known sites and to locate them at new sites. Recording data from herbarium labels should continue. Biological Monitoring Programs: Local field botanists such as Ted Gordon are keeping track of P. wrightianum to some extent. Research Needs: More information is needed on the relative amount of sexual vs. asexual reproduction, the role of seed banks, and the persistence of perennial rosettes. Whether or not fluctuating water regime is sufficient to maintain habitats in early successional stages needs to be determined. The possibility that fire may retard succession as it does for habitats dominated by species of Panicum in the southeastern U.S. (Garren, 1943) should be explored. Summary of Stewardship Needs: Panicum wrightianum occurs on the Atlantic Coastal Plain from Massachusetts to Florida and west to Texas, and in the West Indies and Central America. In New Jersey, it is known from scattered localities in the southern part of the Pine Barrens and adjacent Coastal Plain. It grows on sandy peaty substrates where water levels fluctuate substantially from year to year. Population sizes also fluctuate substantially with plants most frequently found during draught years. Plants are often found at sites that have been disturbed by humans to some extent. Threats are stabilization of its water regime and destruction for development. More information is needed on the present distribution of P. wrightianum in southern New Jersey, its reproductive biology, and the role of the fluctuating water regime and possibly fire in retarding succession at sites where it occurs. Bibliography for Panicum wrightianum scribn.: ANSP. 1990. Data from Specimen Labels in the Herbarium of the Academy of Natural Sciences, Philadelphia. Brown, W.V. 1948. A Cytological Study in the Graminae. Amer. J. Bot. 35(7): 382-395. 66Brown, W.V. and B.N. Smith. 1975. The Genus Dichanthelium (Gramineae). Bull. Torrey Bot. Club 102(1): 10-13. Chase, A. 1914. Panicum wrightianum in Long Island. Rhodora 16: 167. Eleuterius, L.N. & S.B. Jones, Jr. 1969. A Floristic and Ecological Study of Pitcher Plant Bogs in South Mississippi. Rhodora 71: 29-34. Fernald, M.L. 1937. Local Plants of the Inner Coastal Plain of Southeastern Virginia. Rhodora 39: 321-366, 379-415, 433-459, 465-491. Fernald, M.L. 1939. Last Survivors in the Flora of Tidewater Virginia. Rhodora 41: 465-504, 529-559, 564-574. Fernald, M.L. 1943. Virginian Botanizing under Restrictions. Rhodora 45: 357-413, 445-480, 485-511. Fernald, M.L. 1950. Gray's Manual of Botany. 8th ed. American Book Co., New York. lxiv + 1632 pp. Freckmann, R.W. 1981. Realignments in the Dichanthelium acuminatum Complex (Poaceae). Phytologia 48(1): 99-110. Garren, K.H. 1943. Effects of Fire on Vegetation of the Southeastern United States. Bot. Rev. 9(9): 617-654. 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. Gould, B.A. & C.A. Clark. 1978. Dichanthelium (Poaceae) in the United States and Canada. Ann. Missouri Bot. Gard. 65(4): 1088-1132. Hitchcock, A.S. & A. Chase. 1910. The North American Species of Panicum. Contr. U. S. Natl. Herb. 15: 1-396. NJNHP. 1989a. Element Occurrence Summaries. New Jersey Natural Heritage Program, Trenton. NJNHP. 1989b. State Ranking Forms. New Jersey Natural Heritage Program, Trenton. 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. Seymour, F.C. 1969. The Flora of New England. The Charles E. Tuttle Co., Publishers, Rutland. xvi + 596 pp. Sinnott, E.W. 1912. The Pond Flora of Cape Cod. Rhodora 14: 25-34. Sorrie, B.A. 1987. Notes on the Rare Flora of Massachusetts. Rhodora 89(858): 113-196. Spellenberg, R.W. 1975. Autogamy and Hybridization as Evolutionary Mechanisms in Panicum subgenus Dichanthelium (Graminae). Brittonia 27(1): 87-95. Stasz, J.L. 1990. The Maryland-National Capital Park and Planning Commission, Upper Marlboro, MD, personal communication. Webster, R.D. 1988. Genera of North American Paniceae (Poaceae: Panicoideae). Syst. Bot. 13(4): 576-609.