The genus name means fringed style and the species name refers to the dark brown, or castaneous, leaf bases (Flora of North America Editorial Committee 2002).
There are ten existing populations and most of them have over 100 plants with one very large population of thousands of plants. There are three additional populations from the early 1900s that have not been rediscovered and three populations from the late 1800s which are considered extirpated.
Most of the populations have been doing well in the short term. There have been no recent surveys of the smaller populations to determine trends.
This plant has always been rare in New York and while 3 populations are considered extirpated others have been rediscovered. The trend may be downward in the future without control of Phragmites.
The invasion of Phragmites is the largest threat at this time. One population is subject to trampling of the salt marsh.
Control Phragmites invasions in the salt marshes where it exists and prevent new incursions. Natural buffers should be established around the salt marshes to decrease pollution runoff and other direct human disturbances.
There is a need for research into the factors that control the population size of this plant.
In New York, marsh fimbry has been found exclusively in high salt marshes, often at the landward edge, and in adjacent areas of open salt shrub vegetation (New York Natural Heritage Program 2010). Salt marsh and brackish marsh inland (FNA 2002). Brackish coastal marshes, seldom in alkaline sites inland (Gleason and Cronquist 1991).
This species is currently known from eastern Suffolk County on Long Island and historically from Queens. There are old, unconfirmed reports from Staten Island and Westchester County.
This plant grows in coastal salt marshes from Long Island south to the panhandle of Florida and west to South Texas. There are some additional inland populations in North and South Carolina and Louisiana. It also extends south into Mexico and the West Indies.
Fimbristylis is a genus of the sedge family (Cyperaceae) with only a few species found in New York. It is a perennial, clump-forming species, with deep-set stout leaf bases, growing from 80 to 150 centimeters tall. The leaves have dark brown (castaneous) bases and blades only 1 or 2 millimeters wide. The stems are taller than the leaves, and bear a (usually) compound infloresence with ascending branches, subtended by leafy bracts. The spikelets are brown and 5 to 20 centimeters long. Each bears flowers which lack a perianth and have bifid styles, maturing to brown achenes 1.5 to 2 millimeters long and finely striped/reticulate (FNA 2002, USDA 2011).
Although it may be possible to identify Marsh Fimbry in vegetative form, fruiting specimens are most easily identified.
Fimbristylis species might be mistaken for members of the genera Scirpus or Fuirena, which differ from Fimbristylis by having perianth bristles, normally persistent on the achenes. Only two species of Fimbristylis are known to persist in New York: F. castanea and F. caroliniana. F. caroliniana is much more common than F. castanea, and differs from it by being clonal with long slender rhizomes, and lacking the hard, leathery, dark brown leaf bases of F. castanea.
Fimbristylis puberula var. puberula and F. autumnalis were once found in New York but are now considered to be extirpated. F. puberula var. puberula is rhizomatous, with mostly shorter spikelets (5 -10 millimeters) F. autumnalis is an annual species with flat leaf blades. Both species lack theleathery, dark brown leaf bases of F. castanea (FNA 2002).
This plant is best surveyed for when fruits are present, in late July through October.
The time of year you would expect to find Marsh Fimbry flowering and fruiting in New York.
Fimbristylis castanea (Michx.) Vahl
Flora of North America Editorial Committee. 2002. Flora of North America, North of Mexico. Volume 23. Magnoliophyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York. 608 pp.
Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.
Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.
New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.
New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.
USDA, NRCS. 2011. The PLANTS Database (http://plants.usda.gov, 25 January 2011). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
USDA, Natural Resources Conservation Service, PLANTS Database [USDA PLANTS]. http://plants.usda.gov/. Accessed 2007.
Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
Information for this guide was last updated on: May 11, 2011
Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Fimbristylis castanea. Available from: https://guides.nynhp.org/marsh-fimbry/. Accessed March 23, 2023.