- Scientific name: Scleria pauciflora
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
- Endangered (MA Endangered Species Act)
Description
Papillose nut-sedge is a slender, perennial species in the sedge family (Cyperaceae). Stems arise from short, branched, knotty rhizomes with fibrous roots. Plants are 10-50 cm (3.9-19.7 in) tall, forming small clumps with numerous bluish-green leaves (1-2.5 mm; 0.04-0.1 in wide) and 3 to 10 flowering culms. A larger number of flowering culms may develop after fire. Flowering culms often have a solitary terminal inflorescence that is sessile and subtended by a leafy bract, and a second short-stalked inflorescence lower on the stem. The scales are ovate. Achenes (dry, one-seeded fruits) are 1-2.5 mm (0.04-0.1 in) long (up to 5 mm; 0.2 in), white, and subglobose, with a short stiff tip. Achenes are covered with horizontally arranged warty projections. A disk called the hypogynium, found at the base of the achene, has six rounded tubercles or knobby projections, a diagnostic characteristic of this species. Flowering stems often produce only 1 to 4 fruits. Seeds may require the heat of a fire, physical abrasion, or long periods of saturation to break dormancy and germinate. Studies throughout the range suggest that seeds of papillose nut-sedge may remain viable in the soil seed bank for many decades until conditions are favorable for germination.
Aids to Identification: Technical manuals should be consulted to distinguish nut-sedge species. Papillose nut-sedge is characterized by:
- Cespitose growth form
- White achenes with warty projections
- Hypogynium with six rounded tubercles
Papillose nut-sedge varieties are separated by the degree of plant hairiness. Scleria pauciflora var. caroliniana has spreading, weak hairs, 0.5-1 mm (0.02-0.04 in) long. Scleria pauciflora var. pauciflora is glabrous or sparsely hairy, with hairs less than 0.4 mm (0.016 in) long.
Papillose nut-sedge may occur with another rare Scleria species, tall nut-sedge (S. triglomerata), which is also listed as Endangered in Massachusetts. Tall nut-sedge is a much larger plant with sparse, bright yellow-green leaves, long culms (40-100 cm; 15.7-39.4 in), and large, shiny white achenes that have no surface detailing. Pondshore nut-sedge (S. reticularis) is an uncommon annual species found on pond shores that is easily distinguished from papillose nut-sedge by its smaller size and different achene surface texture.
Life cycle and behavior
This is a perennial species.
Population status
Both Scleria pauciflora var. caroliniana and S. pauciflora var. pauciflora are listed under the Massachusetts Endangered Species Act as Endangered. All listed species are protected from killing, collecting, possessing, or sale, and from activities that would destroy habitat and thus directly or indirectly cause mortality or disrupt critical behaviors. MassWildlife’s Natural Heritage & Endangered Species Program database has 27 records from 6 counties: Barnstable, Dukes, Franklin, Nantucket, Plymouth, and Worcester. Twelve of those records are within the last 25-year period.
Distribution in Massachusetts
1999-2024
Based on records in the Natural Heritage Database
Distribution and abundance
Scleria pauciflora var. caroliniana occurs from Florida north to Massachusetts and New York, west to Kentucky, Illinois, Missouri, Kansas, Oklahoma, and Texas. S. pauciflora var. pauciflora has a similar but spottier distribution and extends farther north into New Hampshire and Ontario, Canada.
Habitat
Papillose nut-sedge occurs in dry to moist sandy soils of maritime grasslands, pine and oak barrens, disturbed forest openings, and powerline rights-of-way. Common plant associates are little bluestem (Schizachyrium scoparium), scrub oak (Quercus ilicifolia), pennsylvania sedge (Carex pensylvanica), skydrop aster (Aster patens), pinweed (Lechea minor), and sweet goldenrod (Solidago odora). Papillose nut-sedge also occurs less frequently with rare species such as bushy rockrose (Crocanthemum dumosum), sandplain flax (Linum intercursum), sandplain blue-eyed grass (Sisyrinchium fuscatum), and tall nut-sedge (Scleria triglomerata).
Healthy habitats are vital for supporting native wildlife and plants. Explore habitats and learn about conservation and restoration in Massachusetts.
Threats
Papillose nut-sedge populations are threatened by development pressure, particularly on unprotected lands on Cape Cod, Martha’s Vineyard, and Nantucket. Populations on permanently protected sites are threatened by plant succession, fire suppression, and lack of disturbance. Small, isolated populations in fragmented habitats may also be subject to inbreeding depression.
Conservation
Populations should be monitored to evaluate population dynamics, critical ecological processes, land-use history, and potential threats. Additional surveys are needed for Scleria pauciflora var. pauciflora. Active management may be needed to maintain and restore early successional habitats for papillose nut-sedge, including prescribed fire, mowing, or other mechanical treatments in combination with light soil scarification. However, careful planning is needed as disturbances such as brush hogging or bulldozing can potentially eliminate plants and seeds within small populations. All active management of rare plant populations (including invasive species removal) is subject to review under the Massachusetts Endangered Species Act and should be planned in close consultation with the MassWildlife’s Natural Heritage & Endangered Species Program.
References
Core, E.L. 1936. The American species of Scleria. Brittonia 2: 1-105.
Fernald, M.L. 1950. Gray’s Manual of Botany, 8th edition. American Book Company, Boston, MA.
NatureServe. 2010. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, VA.http://www.natureserve.org/explorer.
Reznicek, A.A., J.E. Fairey, and A.T. Whittemore. 2002. Scleria. P.J. Bergius. Pages 242-251 in Flora of North America Editorial Committee (Editors), Flora of North America North of Mexico, Volume 23. Cyperaceae. OxfordUniv. Press, NY.
Zaremba, R. E. 2004. Scleria pauciflora Muhlenberg ex Willdenow var. caroliniana Alph. Wood and Scleria pauciflora Muhlenberg ex Willdenow var. pauciflora (Few-flowered nut-rush) Conservation and Research Plan for New England. New England Wildflower Society, Framingham, MA.
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| Date published: | May 12, 2025 |
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