''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
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 ...
, 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 and have become a model for the study of chromosome evolution and meiotic recombination in holocentric plants. The genomes of ''
Rhynchospora pubera'', ''
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'' - 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'' - Southeast
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 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'' - Slender beakrush. Eastern
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 capitellata'' - Brownish beak-sedge
*''
Rhynchospora colorata'' - White star sedge. Southeast
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 fusca'' - Brown 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 ...
.
*''
Rhynchospora glomerata'' - Clustered beak-sedge. North America.
[''Rhynchospora glomerata'' (L.) Vahl](_blank)
USDA Plants Profile. 23 Nov 2011
*''
Rhynchospora inexpansa'' - Southeastern North America and West Indies
*''
Rhynchospora knieskernii'' - Knieskern's beak-sedge.
*''
Rhynchospora longisetis''
*''
Rhynchospora macrostachya'' - Tall horned beaksedge. Eastern North America.
*''
Rhynchospora megalocarpa'' -
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 '' - Florida
*''
Rhynchospora nervosa'' - 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'' -
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: ...
.
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