''Rhynchospora'' (beak-rush or beak-sedge) is a genus of about 400 species of

sedges The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large; botanists have described some 5,500 known species in about 90 generathe largest being the "true sedges" (genu ...

with a

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

. The genus includes both annual and perennial species, mostly with erect 3-sided stems and 3-ranked leaves. The achenes bear a beak-like tubercule (hence the name “beak-rush”, although the plants are

, not rushes) and are sometimes subtended by bristles. Many of the species are similar in vegetative appearance, and mature fruits are needed to make a positive identification. The inflorescences (spikelets) are sometimes subtended by bracts which can be leaf-like or showy. Members of this genus have

holocentric chromosomes Holocentric chromosomes are chromosomes that possess multiple kinetochores along their length rather than the single centromere typical of other chromosomes. They were first described in cytogenetic experiments in 1935. Since this first observation ...

and have become a model for the study of chromosome evolution and meiotic recombination in holocentric plants. The genomes of ''

Rhynchospora pubera ''Rhynchospora'' (beak-rush or beak-sedge) is a genus of about 400 species of sedges with a cosmopolitan distribution. The genus includes both annual and perennial species, mostly with erect 3-sided stems and 3-ranked leaves. The achenes bear a ...

'', '' R. breviuscula'', and '' R. tenuis'' have been published in 2022.

Ecology

''Rhynchospora'' occurs on all continents except Antarctica, but is most diverse in the neotropics.Thomas, W.W. 1992. A synopsis of ''Rhynchospora'' (Cyperaceae) in Mesoamerica. ''Brittonia'' 44:14–44. It is most frequent in sunny habitats with wet, acidic soils.Kral, R. 2002. ''Rhynchospora''. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 15+ vols. New York and Oxford. Vol. 23 pp. 200-239. In marshes and savannas, ''Rhynchospora'' may be the dominant form of vegetation.

Taxonomy

Contemporary taxonomic treatments include ''Rhynchospora'' and the related genus ''Pleurostachys'' in the tribe Rhynchosporae, a well-supported clade within Cyperaceae.Muasya, A. M., J. Bruhl, D. A. Simpson, A. Culham and M. W. Chase. 2000. Suprageneric phylogeny of Cyperaceae: A combined analysis. pp. 593–601. In: K. Wilson and D. Morrison (eds.) Monocots: Systematics and Evolution. CSIRO: Melbourne. The most comprehensive monograph of the genus Kükenthal, G. 1949-1951. Vorarbeiten zu einer Monographie der Rhynchosporoideae. ''Rhynchospora''. Bot. Jahrb. Syst. 74, 75 divides ''Rhynchospora'' into two subgenera and 29 sections. A recent molecular analysis Thomas W.W., A.C. Araujo, and M.V. Alves. 2009. A Preliminary Molecular Phylogeny of the Rhynchosporae (Cyperaceae). Botanical Review 75:22-29. identifies two primary clades within the genus, with well-supported subgroups that agree with several of the sections identified by Kükenthal. However, this molecular analysis also suggests that ''Pleurostachys'' is embedded within one of the primary clades of ''Rhynchospora'' and that several of the recognized sections are not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. ;Selected species: *''

Rhynchospora alba ''Rhynchospora alba'', the white beak-sedge, is a plant in the sedge family, Cyperaceae. It is a tufted herbaceous perennial around 50 cm tall, with white inflorescences that flower in August. The fruit of the sedge is a small achene with a ...

'' - White beak-sedge.

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

*''

Rhynchospora caduca ''Rhynchospora caduca'', commonly called anglestem beaksedge, is a species of flowering plant in the sedge family (Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, ...

'' - Southeast

*'' Rhynchospora californica'' - California beaked-rush, occurring in Marin and

Sonoma County, California Sonoma County ( ) is a county located in the U.S. state of California. As of the 2020 United States census, its population was 488,863. Its seat of government and largest city is Santa Rosa. Sonoma County comprises the Santa Rosa-Petaluma ...

*''

Rhynchospora capillacea ''Rhynchospora capillacea'' is a species of sedge known by the common names needle beaksedge, slender beakrush and needle beakrush. It is native to eastern North America from Labrador to Alberta, and south to Texas. It grows in wet, usually calc ...

'' - Slender beakrush. Eastern

*'' Rhynchospora capitellata'' - Brownish beak-sedge *''

Rhynchospora colorata ''Rhynchospora colorata'', also known as starrush whitetop, white star sedge and white-topped sedge, is a perennial flowering plant in the sedge family. It has white bracts, giving it the appearance of white petals with long, green points. It is ...

'' - White star sedge. Southeast

. *''

Rhynchospora fusca ''Rhynchospora fusca'' (vernacular name: brown beaksedge or brown beak-sedge) is a species of sedge belonging to the family Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wik ...

'' - Brown beak-sedge.

. *''

Rhynchospora glomerata ''Rhynchospora'' (beak-rush or beak-sedge) is a genus of about 400 species of sedges with a cosmopolitan distribution. The genus includes both annual and perennial species, mostly with erect 3-sided stems and 3-ranked leaves. The achenes bear a ...

'' - Clustered beak-sedge. North America.''Rhynchospora glomerata'' (L.) Vahl
USDA Plants Profile. 23 Nov 2011 *''

Rhynchospora inexpansa ''Rhynchospora inexpansa'', commonly called nodding beaksedge, is a species of flowering plant in the sedge family (Cyperaceae). It is native to North America, where it is found in the southeastern United States and West Indies. Its typical natur ...

'' - Southeastern North America and West Indies *''

Rhynchospora knieskernii ''Rhynchospora knieskernii'' is a rare species of sedge known by the common name Knieskern's beaksedge. It is endemic to the state of New Jersey in the United States, where it occurs naturallyin the Pine Barrens. Reports have cited it present in ...

'' - Knieskern's beak-sedge. *''

Rhynchospora longisetis ''Rhynchospora longisetis'' is a species of plant in the family Cyperaceae first described by Robert Brown. No subspecies listed in the Catalogue of Life The Catalogue of Life (CoL) is an online database that provides an index of known specie ...

'' *''

Rhynchospora macrostachya ''Rhynchospora macrostachya'', the tall horned beaksedge or tall beaksedge, is a plant in the sedge family, Cyperaceae. It is a perennial. Conservation status in the United States It is listed as threatened in Connecticut Rhynchospora megalocarpa ''Rhynchospora megalocarpa'', commonly called sandyfield beaksedge, is a species of flowering plant in the sedge family (Cyperaceae). It is native to North America, where it is found in the southeastern United States. Distribution ''Rhynchosp ...

'' -

Southeastern United States The Southeastern United States, also known as the American Southeast or simply the Southeast, is a geographical List of regions in the United States, region of the United States located in the eastern portion of the Southern United States and t ...

*''

Rhynchospora megaplumosa ''Rhynchospora megaplumosa'', the Manatee beaksedge, is a plant species endemic to a small region in central Florida. It is known from only 4 Counties: Polk, Hillsboro, Manatee and Sarasota Sarasota () is a city in and the county seat of Sar ...

'' - Florida *''

Rhynchospora nervosa ''Rhynchospora'' (beak-rush or beak-sedge) is a genus of about 400 species of sedges with a cosmopolitan distribution. The genus includes both annual and perennial species, mostly with erect 3-sided stems and 3-ranked leaves. The achenes bear a ...

'' - Tropical

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

. *'' Rhynchospora rariflora'' - Southeastern North America, West Indies, Central America *'' Rhynchospora scirpoides'' - North America *'' Rhynchospora waspamensis'' -

References

External links

interactive identification key

Other sources

* Acevedo-Rodríguez, P. & Strong, M.T. (2005). Monocotyledons and Gymnosperms of Puerto Rico and the Virgin Islands. Contributions from the United States National Herbarium 52: 1–415. * Gale, S. 1944. ''Rhynchospora'' sect. ''Eurhynchospora'' in Canada, the United States and the West Indies. Rhodora 46: 80–134, 159–197, 255–278. * Kral, R. 1996. Supplemental notes on ''Rhynchospora crinipes'' and related species in sect. ''Fuscae'' (Cyperaceae). Sida 17: 385–411. * Strong, M.T. (2006). Taxonomy and distribution of ''Rhynchospora'' (Cyperaceae) in the Guianas, South America. Contributions from the United States National Herbarium 53: 1–225. * Thomas, W. W. 1994. 1. ''Rhynchospora'' Vahl. 6: 404–422. In G. Davidse, M. Sousa Sánchez & A.O. Chater (eds.) Flora Mesoamericana. Universidad Nacional Autónoma de México, México, D. F. {{Authority control Cyperaceae genera Taxa named by Martin Vahl