ELEMENT STEWARDSHIP ABSTRACT FOR CAREX MITCHELLIANA November 29, 1990 Stewardship Abstract No.: 005 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: CAREX MITCHELLIANA Curtis (Cyperaceae) Element Code: PMCYPO38RO Preparer: Alfred E. Schuyler Common Name: Mitchell's Sedge Description: Habit: perennial rhizomatous herb with erect stems having narrow elongate sheathing leaves and minute flowers in cylindric pistillate and staminate spikes. Stem: culms in tufts at tips of short rhizomes, sharply 3- angled, up to 1.3 m tall. Leaves: 2-4 leaves restricted to basal quarter of culm, up to 9 mm wide, with fine hairs on sheaths (rarely glabrous). Inflorescence: 2-4 pistillate spikes in axils of sheathless (or nearly so) leaf-like bracts and 1-3 staminate spikes above the pistillate. Spikes: pistillate spikes up to 8 cm long and 7.5 mm wide, lower ones pendant on peduncles up to 3 cm long, often with some staminate flowers at apex. Staminate spikes up to 7.5 cm long and 3.5 mm wide. Pistillate scales near base of spike up to 6.5 mm long with awns up to 3.5 mm long, apex of scale body usually truncate. Staminate scales up to 4.5 mm long with awns up to 1.9 mm long or awnless. Perigynia ascending, glabrous, ovate to broadly ovate, lenticular and closely enveloping achene, up to 4.1 mm long and 2.2 mm wide, densely granular-papillate, usually 1-4 nerved on both surfaces. Flowers: style with 2 stigmas, stamens 3. Fruits: achenes elliptic to rhomboid-elliptic, lenticular, up to 2.3 mm long and 1.5 mm wide, deep reddish-brown to dark brown. Overwintering Characteristics: tufts of leaves usually apparent in winter, becoming brown as season progresses. Chromosomes: Bruederle et al. (1989) reported n=33 in plants near Manahawkin, New Jersey. Distinction from Related Species: Carex mitchelliana closely resembles C. crinita var. crinita Lam., C. crinita var. brevicrinis Fern., and C. gynandra Schw. The following characteristics of C. mitchelliana distinguish it from these species: 1) papillate, nerved, uninflated, ovate perigynia; 2) fine hairs on leaf sheaths; 3) truncate apex of pistillate scale body; and 4) uncontorted achenes. Although some of these characteristics are found in one of the other taxa (Bruederle et al. 1989), taken as a group they are effective for identification purposes. Habitat: Historically the range of C. mitchelliana extended from east- central Massachusetts south to northern Florida and west to western Pennsylvania and western Alabama (Bruederle, 1989). In the northeastern portion of its range, it occurs on the Atlantic Coastal Plain in Massachusetts, New York, New Jersey, Delaware, and Virginia with disjunct occurrences in western Pennsylvania, and eastern Tennessee. Populations are most frequent in northwestern Georgia and eastern Alabama and much less frequent northeastward. Carex mitchelliana usually grows in swamp and floodplain forests and thickets, but also may be found in wet meadows, along stream edges and ponds, and in roadside ditches. In New Jersey, C. mitchelliana is restricted to the Coastal Plain exclusive of the Pine Barrens where it is known from 6 extant occurrences and 13 additional historic sites (NJNHP, 1989b). It grows in swamps and occasionally is found in ditches along roads through swamps (Bruederle, pers. comm., 1990). It is shade tolerant but probably would not survive under a closed canopy. Biology/Ecology: Carex mitchelliana fruits in July and August. Allozyme analysis (Bruderle and Manos, 1986) of genetic variability indicated that this species is self-pollinated. There is greater apportionment of genetic variability between populations than within. In New Jersey, C. mitchelliana does not exploit habitats disturbed by humans as much as C. crinita and C. gynandra. Although C. mitchelliana is known from at least one roadside ditch, where it is abundant, this habitat is adjacent to a less disturbed habitat in forested wetland. This ditch is periodically mowed, which apparently does not have an adverse impact on the population and may enhance it to some extent (Bruederle, pers. comm., 1990). Most New Jersey habitats of C. mitchelliana are in openings in forested wetlands that are in a late successional stage. Most populations are small and most reproduction probably is asexual from rhizomes. Data is meager concerning fruit production and dispersal. The hard achenes may be dispersed by birds and some probably persist in a seed bank near the parent plant. Determination of Element Occurrence (EO) Quality: Most extant habitats of C. mitchelliana in New Jersey are high quality wetlands in a late successional stage. There is no evidence of low vigor or vitality of individual plants and some disturbances that increase canopy openings may benefit them. Threats: Habitat destruction and degradation are the greatest threats to this species. The plants occur on portions of the New Jersey Coastal Plain that are more likely to undergo impacts from development. Since C. mitchelliana grows in a limited habitat in a late successional stage, restoration after severe degradation would be difficult or impossible. Other potential threats include alterations of the water regime (e.g., water diversion, ground water depletion) and lumbering. Succession may also be a problem if it results in a dense canopy that substantially reduces light. Land Protection Specifications: Substantial tracts of forested wetlands that contain sites for C. mitchelliana should be protected. Protection of the surrounding watershed is essential to maintain the proper water regime. Recovery Potential: Restoration of severely damaged or depleted sites would be difficult. Most reproduction appears to be clonal in tufts, a condition that would not facilitate recolonization. Less severe damage, not affecting light, moisture, and substrate conditions, may be tolerated by the plants. Biological Monitoring Needs: Need information on what changes are occurring in population sizes from year to year and need to search for new sites. Biological Monitoring Procedures: Periodic visits to selected scattered sites should be made to record fluctuations in population size. Searches for new sites should be conducted. Biological Monitoring Programs: Leo Bruederle has conducted research on the systematics and ecology of this species and continues to be interested in its conservation. Research Needs: More information is needed on the role of sexual reproduction in maintaining viable populations. Fruit dispersal and seedling establishment are areas where knowledge is incomplete. Summary of Stewardship Needs: Carex mitchelliana is a rare sedge in New Jersey where it is near the northern limit of its range. It grows in swamps on the Coastal Plain exclusive of the Pine Barrens where it is vulnerable to development. Most populations are small and reproduction appears to be mostly asexual within clonal tufts. Recovery potential probably would be low for severely degraded habitats because it would be difficult to restore them to a late successional stage. Also the tufted growth form restricts the effectiveness for recolonization of habitats by asexual reproduction. Population sizes should be monitored and searches should be made for new sites. Research needs should focus on the role of sexual reproduction in maintaining viable populations, as well as on fruit dispersal and seedling establishment. Bibliography for Carex mitchelliana curtis: Bruederle, L.P. 1990. Rutgers Blueberry and Cranberry Research Center, Chatsworth, NJ, personal communication. Bruederle, L.P. & D.E. Fairbrothers. 1986. Allozyme Variation in Populations of the Carex crinita Complex. Syst. Bot. 11(4): 583-594. Bruederle, L.P., D.E. Fairbrothers & S.L. Hanks. 1989. A Systematic Circumscription of Carex mitchelliana (Cyperaceae) with Reference to Taxonomic Status. Amer. J. Bot. 76(1): 124-132. Bruederle, L.P. & P.S. Manos. 1986. Conservation Genetics of the Rare Sedge Carex mitchelliana M. A. Curtis (Cyperaceae). Amer. J. Bot. 73(5): 663. Carr, L.G. 1940. Further Notes on the Coastal Floral Elements in the Bogs of Augusta County, Virginia. Rhodora 42: 86-93. Fernald, M.L. 1942. The Seventh Century of Additions to the Flora of Virginia. Rhodora 44: 341-405, 416-452, 457-478. Fernald, M.L. 1947. Additions to and Subtractions from the Flora of Virginia. Rhodora 49: 85-115, 121-142, 145-159, 175-194. 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. Fernald, M.L. 1950. Gray's Manual of Botany. 8th ed. American Book Co., New York. lxiv + 1632 pp. 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. Griscom, L. & H.K. Svenson. 1928. Carex mitchelliana and Other Rare Plants near Cohasset, Massachusetts. Rhodora 30: 198-199. NJNHP. 1989a. Element Occurrence Summaries. New Jersey Natural Heritage Program, Trenton. NJNHP. 1989b. State Ranking Forms. New Jersey Natural Heritage Program, Trenton. Seymour, F.C. 1969. The Flora of New England. The Charles E. Tuttle Co., Publishers, Rutland. xvi + 596 pp. Weatherby, C.A. 1923. Some Critical Plants of Atlantic North America. Rhodora 25: 17-23.