Rhynchospora capitellata(Michx.) Vahl

Brownish beaksedgeSmallhead beakrushbrownish beaksedge

WFO wfo-0000514649 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Rhynchospora capitellata, photographed by Ryan Sorrells
fig. a Ryan Sorrells, CC BY 4.0 / 2021-08-26 / obs. 153597723
Rhynchospora capitellata, photographed by Ryan Sorrells
fig. b Ryan Sorrells, CC BY 4.0 / obs. 153599306
Rhynchospora capitellata, photographed by Bonnie Semmling
fig. c Bonnie Semmling, CC BY 4.0 / obs. 187908163
Rhynchospora capitellata, photographed by Roy Boyle
fig. d Roy Boyle, CC0 1.0 / obs. 88581101
Rhynchospora capitellata, photographed by Alan Weakley
fig. e Alan Weakley, CC0 1.0 / obs. 87897337
Rhynchospora capitellata, photographed by Quinten Wiegersma
fig. f Quinten Wiegersma, CC BY 4.0 / obs. 86238525
Rhynchospora capitellata, photographed by Quinten Wiegersma
fig. g Quinten Wiegersma, CC BY 4.0 / obs. 86238620
Rhynchospora capitellata, photographed by Chris Hoess
fig. h Chris Hoess, CC BY-SA 4.0 / obs. 21838860

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 36 botanical countries

Regions where Rhynchospora capitellata is native: Alabama, Arkansas, California, Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, New Brunswick, New Hampshire, New Jersey, New York, North Carolina, Nova Scotia, Ohio, Ontario, Oregon, Pennsylvania, Québec, Rhode I., Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin AlabamaArkansasCaliforniaConnecticutGeorgiaIllinoisIndianaKansasKentuckyMaineMarylandMassachusettsMichiganMinnesotaMississippiMissouriNew BrunswickNew HampshireNew JerseyNew YorkNorth CarolinaNova ScotiaOhioOntarioOregonPennsylvaniaQuébecTennesseeTexasVermontVirginiaWest VirginiaWisconsin DelawareDistrict of ColumbiaRhode I.
Native distribution of Rhynchospora capitellata, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Alabama ALA NORTHERN AMERICA
Arkansas ARK
California CAL
Connecticut CNT
Delaware DEL
District of Columbia WDC
Georgia GEO
Illinois ILL
Indiana INI
Kansas KAN
Kentucky KTY
Maine MAI
Maryland MRY
Massachusetts MAS
Michigan MIC
Minnesota MIN
Mississippi MSI
Missouri MSO
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New York NWY
North Carolina NCA
Nova Scotia NSC
Ohio OHI
Ontario ONT
Oregon ORE
Pennsylvania PEN
Québec QUE
Rhode I. RHO
Tennessee TEN
Texas TEX
Vermont VER
Virginia VRG
West Virginia WVA
Wisconsin WIS

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Where it actually grows measured, from 686 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -14.9 °C -7.5 °C -1.1 °C
Warmest month, mean daily high 22.0 °C 25.8 °C 30.7 °C
Annual rainfall 887 mm 1,174 mm 1,536 mm
Rainfall in the driest quarter 137 mm 247 mm 328 mm

It is found where winters bring hard frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 686 research-grade observations of Rhynchospora capitellata that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

Also published as 13 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Phaeocephalum glomeratum var. minus (Britton) Farw.
  • Rhynchospora capitellata f. capitellata
  • Rhynchospora capitellata f. controversa (S.F.Blake) Gale
  • Rhynchospora capitellata f. discutiens (C.B.Clarke ex Britton) Gale
  • Rhynchospora capitellata var. controversa S.F.Blake
  • Rhynchospora capitellata var. discutiens (C.B.Clarke ex Britton) S.F.Blake
  • Rhynchospora capitellata var. minor (Britton) S.F.Blake
  • Rhynchospora glomerata f. discutiens (C.B.Clarke ex Britton) Fernald
  • Rhynchospora glomerata var. capitellata (Michx.) Kük.
  • Rhynchospora glomerata var. discutiens C.B.Clarke ex Britton
  • Rhynchospora glomerata var. minor Britton
  • Rhynchospora smallii Britton
  • Schoenus capitellatus Michx.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.