Rhynchospora Alba
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''Rhynchospora alba'', the white beak-sedge, is a plant in the sedge family,
Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...
. It is a tufted
herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...
perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
around 50 cm tall, with white
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s that flower in August. The fruit of the sedge is a small
achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...
with a characteristic beak-like cap. It is dispersed by wind or falls by gravity, leading to individuals existing in tight clumps. The species favours wet, acidic and nutrient poor soils, thriving in ''
Sphagnum ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store water, since ...
''-dominated bogs, but also
peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...
y
grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...
s. As such, it is often used as a positive indicator for bog and
mire A peatland is a type of wetland whose soils consist of Soil organic matter, organic matter from decaying plants, forming layers of peat. Peatlands arise because of incomplete decomposition of organic matter, usually litter from vegetation, du ...
ecosystem health Ecosystem health is a metaphor used to describe the condition of an ecosystem.Rapport, David (1998). "Defining ecosystem health." Pages 18-33 in Rapport, D.J. (ed.) (1998). ''Ecosystem Health.'' Blackwell Scientific. Ecosystem condition can vary a ...
. The species was first described by
Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in 1753 under a different
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
and name, ''Schoenus albus'', but was subsequently reclassified into the novel genus ''
Rhynchospora ''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 ...
'' by
Vahl Vahl is a surname. Notable people with the surname include: * Christian-Friedrich Vahl (born 1955), German cardiac surgeon * Emanuel Vahl (born 1938), Ukrainian-Israeli composer *Herbert-Ernst Vahl, German SS general *Jens Vahl (1796–1854), Danis ...
in 1805. It has a wide range across the Northern Hemisphere, extending from the inland
wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
s of
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, across
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 ...
to the
Korean Peninsula Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically divided at or near the 38th parallel between North Korea (Dem ...
. Due to this large range, there is considerable variation between populations, and numerous varieties have been identified. The plant has few uses, though it is used as an ornamental in the UK.


Description

''Rhynchospora alba'' is a
perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
herb between 10 and 50 cm in height, though plants up to 75 cm tall can be found in
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 ...
. The plant grows in tight clumps, meaning it is often difficult to distinguish individual stems. The plant consists of a single erect stem, which is three-angled and thin, usually 0.5–1 mm thick. The leaves attached to the stem are three-ranked (in spirals around the three edges of the stem) and parallel veined, extending up to 15 cm in length /sup>, though none overtop the stem. Each leaf is differentiated into a green or straw coloured sheath, which hugs the stem, and a grey/green blade, which is flat and slender (0.7–2 mm) and tapers to a blunt tip. In some specimens, the margins of the blade are sparsely covered in hairs. Unlike many
sedge The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...
species, there is no
ligule A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above g ...
(outgrowths at the meeting of the blade and sheath). At the base of the plant, the leaves have no blade, and only the sheaths are present. These are often subtending a 10–20 mm bud, which will overwinter and grow a new plant in spring. While most ''
Rhynchospora ''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 ...
'' have large
rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...
s (tuber-like stems below the soil surface), ''R. alba'' has very small rhizomes, or none at all, and very shallow root systems. This reflects its different life history to many other
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 ...
– ''R. alba'' loses all but the basal overwintering bud during the winter, while most other species retain and store nutrients in well-developed rhizome and
root In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...
structures.


Reproductive structures

''Rhynchospora alba'' flowers in August, and these flowers are arranged into white
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s in a hierarchy of units. Each individual flower is surrounded a white (or brown in older tissues), leaf-like structure called a '
glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flow ...
'. These glumes are grouped into egg-shaped '
spikelet A spikelet, in botany, describes the typical arrangement of the inflorescences of grasses, sedges and some other monocots. Each spikelet has one or more florets. The spikelets are further grouped into panicles or spikes. The part of the sp ...
s' between 3 and 6 mm in length, and two to seven of these spikelets are clustered together into a hemispheric cluster, making the
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
. As with many other ''Rhynchospora'', there are 4–5 glumes in each spikelet, with the bottom one or two glumes being sterile (they do not contain flowers) and the top three glumes alternating fertile, sterile, fertile. As such there are usually one or two flowers per spikelet. Most plants have between one and three inflorescences growing off the stem, each subtended by a short leaf-like
bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...
, about 2–3 x the length of the inflorescence. Each flower is
bisexual Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females. It may also be defined as the attraction to more than one gender, to people of both the same and different gender, or the attraction t ...
, comprising a superior
ovary The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/ oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are end ...
with a bifurcating style and 2–3
anthers The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...
(each 1 mm in length). The
petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...
s and
sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...
s (
perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower. It is a structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepal ...
) are homogenous and highly modified, forming ring of 9–13 bristles with downward-facing barbs. After
pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...
the flower develops into an
achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...
– a dry fruit that is indehiscent (it does not open at maturity) and contains a single seed. This is composed of a 2 mm x 1 mm, egg-shaped achene body and the remnants of the style base of the flower, which forms a 1 mm beak-like structure called the tubercle. The perianth bristles are also retained, and these are shorter than, or the same length as, the achene and tubercle combined. The lengths of both the tubercle and perianth bristles are key characters for distinguishing ''R. alba'' from other ''Rhynchospora'' species.


Similar species

White beak-sedge closely resembles a number of other sedges, including the brown beak-sedge ( ''R. fusca'') and large beak-sedge ( ''R. macra''). It can be distinguished from other species by the reduced size of its rhizomes, the length of the tubercle and perianth bristles on the fruit, and the presence of downward facing barbs on the bristles.


Etymology

The genus ''Rhynchospora'' derives from the Greek ''Rhynkos'' – "beak" and ''spora'' "seed". This, along with the genus’ common name beak-sedge, refers to the long beak-like tubercle at the top of the achene fruit. This is characteristic to the entire genus and is often used for intra-generic classification. The species name ''alba'' derives from the Latin ''albus'', or white, and refers to the white glumes surrounding each flower, which give the inflorescence its colour. The species has multiple common names, the most common being white beak-sedge, again referring to the inflorescence colour and shape of the tubercle. It is also known as white beak-rush, though this is misleading, as it is not in the rush family.


Habitat and ecology

''Rhynchospora alba'' favours
acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...
ic, nutrient poor conditions and is found across a range of wetland environments. It is most commonly found in
ombrotrophic Ombrotrophic ("cloud-fed"), from Ancient Greek ὄμβρος (''ómvros'') meaning "rain" and τροφή (''trofí'') meaning "food"), refers to Soil, soils or vegetation which receive all of their water and nutrients from precipitation, rather ...
bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and musk ...
s (where plant nutrients are only obtained through rainfall and
dry deposition In the physics of aerosols, deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: ''dry'' and ''w ...
) and ''
Sphagnum ''Sphagnum'' is a genus of approximately 380 accepted species of mosses, commonly known as sphagnum moss, also bog moss and quacker moss (although that term is also sometimes used for peat). Accumulations of ''Sphagnum'' can store water, since ...
'' moss-dominated communities, where it is one of the few
vascular plant Vascular plants (), also called tracheophytes (, ) or collectively tracheophyta (; ), are plants that have lignin, lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified Ti ...
species present. Studies into nutrient and mass allocation by ''R. alba'' found the plant exhibits much higher rates of nutrient accumulation and loss across the growing season than in other sedges, which rely more heavily on storage and remobilising of nutrients in rhizomes. This is likely related to the much lower levels of
interspecific competition Interspecific competition, in ecology, is a form of competition in which individuals of ''different'' species compete for the same resources in an ecosystem (e.g. food or living space). This can be contrasted with mutualism, a type of symbiosis. ...
experienced by ''R. alba'' in these bogs than other sedges in more grass-dominated environments. It is also found in
peatlands A peatland is a type of wetland whose soils consist of Soil organic matter, organic matter from decaying plants, forming layers of peat. Peatlands arise because of incomplete decomposition of organic matter, usually litter from vegetation, du ...
alongside other sedge species such as ''
Carex ''Carex'' is a vast genus of over 2,000 species of grass-like plants in the family (biology), family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of ge ...
'' species. It has a persistent
seed bank A seed bank (also seed banks, seeds bank or seed vault) stores seeds to preserve genetic diversity; hence it is a type of gene bank. There are many reasons to store seeds. One is to preserve the genes that plant breeders need to increase yield, ...
, with seeds living up to five years. It is therefore often an early re-coloniser in disturbed environments, where it can become the dominant species in so-called ''R. alba'' sedgeland. It is much less dominant of more established communities, however, as it is less capable of outcompeting sedge species with more developed root and rhizome systems. ''Rhynchospora alba'' is
wind-pollinated Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including Poaceae, grasses, Cyperaceae, sedges, and Juncaceae, rushes. ...
and wind-dispersed, so has few close interactions with insect pollinators, but is a major food source for a number of bog-dwelling species, such as '' Paraphlepsius'' leafhoppers in the US.


Distribution

Although most species of ''Rhynchospora'' are found in
tropics The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...
, ''R. alba'' is more restricted to the higher
latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...
s of the
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
, where climatic conditions favour the establishment of
bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and musk ...
s and fens. It has a wide
boreal Boreal, northern, of the north. Derived from the name of the god of the north wind from Ancient Greek civilisation, Boreas (god), Boreas. It may also refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernand ...
distribution and is commonly found in the US (north of
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
and
South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...
),
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, Europe, the
Caucasus The Caucasus () or Caucasia (), is a region spanning Eastern Europe and Western Asia. It is situated between the Black Sea and the Caspian Sea, comprising parts of Southern Russia, Georgia, Armenia, and Azerbaijan. The Caucasus Mountains, i ...
, China, Japan and the
Korean Peninsula Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically divided at or near the 38th parallel between North Korea (Dem ...
. It is generally found at lower
altitude Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometr ...
s (below 850 m), but has been found at higher altitudes at the southern edge of its range, for example in China and
Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...
.


Taxonomy and systematics

Owing to the high
biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...
and significant morphological similarity seen across the sedges, ''R. alba'' has a somewhat complex
taxonomic 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation ...
history. The species was first described by
Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in 1753, and was classified in the same genus as bog rushes (due to similarities in inflorescence) under the binomial name ''
Schoenus Schoenus (; , ''schoinos'',  " rush rope"; , "river-measure") was an ancient Egyptian, Greek and Roman unit of length and area based on the knotted cords first used in Egyptian surveying. Length The Greeks, who adopted it from the Egyptians ...
albus''. This classification proved inaccurate, and Martin Henrichsen Vahl reclassified the species in 1805 as ''Rhynchospora alba'', placing it in a novel genus that grouped species with a characteristic beak-like
tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projectio ...
on the achene fruit. ''Rhynchospora alba'' (L.) Vahl is the current accepted species name for the white beak-sedge, but there has been considerable contention around its classification over the last 200 years (see below). Neither Vahl nor Linnaeus provided specific
type specimens In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes t ...
with their descriptions, but a recent typification of ''R. alba'' designated a specimen from Linnaeus' collection as a
lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes ...
.


Contention around ''Rhynchospora'' classification

The classification of ''R. alba'' has come under considerable scrutiny since Vahl's description, due to conflicting
classification Classification is the activity of assigning objects to some pre-existing classes or categories. This is distinct from the task of establishing the classes themselves (for example through cluster analysis). Examples include diagnostic tests, identif ...
s of the genus ''Rhynchospora'' and closely related
taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
. Vahl classified ''Rhynchospora'' based on the tubercle/fruit alone. Other taxonomists, such as
Nees Christian Gottfried Daniel Nees von Esenbeck (14 February 1776 – 16 March 1858) was a prolific German botanist, physician, zoologist, and natural philosopher. He was a contemporary of Goethe and was born within the lifetime of Linnaeus. ...
, only recognised species with bifid styles as ''Rhynchospora'', and moved many species into 11 other
genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
(both novel and pre-existing), all within a wider group called the Rhynchosporae. Bentham and Hooker tried to resolve this conflict by splitting ''Rhynchospora'' into two subgenera – ''Diplostylae'' and ''Haplostylae'' – based on the branching pattern of the
style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...
. This was only partially accepted, however, and many previously described genera, such as '' Dichromena'', were still used, sometimes even replacing ''Rhynchospora''. This persisted until Kükenthal published an extensive treatment of Rhynchosporae in 1949, and classified all 250 known
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
into either ''Rhynchospora'' or the closely related '' Pleurostachys'', with all other names either synonyms or sub-groups. Kükenthal also split ''Rhynchospora'' into subgenera ''Diplostylae'' and ''Haplostylae'', and this classification is still widely used today. The result of this contention is that many ''Rhynchospora'' species have numerous
synonyms A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...
. Those for ''R. alba'' include ''Dichromena alba'' and ''Phaecocacephalum album'', from attempts to rename all ''Rhynchospora''. These synonyms were identified in
monograph A monograph is generally a long-form work on one (usually scholarly) subject, or one aspect of a subject, typically created by a single author or artist (or, sometimes, by two or more authors). Traditionally it is in written form and published a ...
s by Kükenthal and Gale, as well as more recent studies by
Kew Kew () is a district in the London Borough of Richmond upon Thames. Its population at the 2011 census was 11,436. Kew is the location of the Royal Botanic Gardens ("Kew Gardens"), now a World Heritage Site, which includes Kew Palace. Kew is ...
's
World Checklist of Selected Plant Families The World Checklist of Selected Plant Families (usually abbreviated to WCSP) was an "international collaborative programme that provides the latest peer reviewed and published opinions on the accepted scientific names and synonyms of selected p ...
. Many
varieties Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...
and forms of ''R. alba'' have also been described over the last two centuries. Some have subsequently been described as new species – ''R. alba'' var. ''fusca'' was subsequently reclassified as ''R. fusca'' as it was found to have very different morphology. Others, such as ''R. alba'' var ''kiusiana'' and ''R. alba'' f. ''laeviseta,'' are considered synonyms, pending more work on the genetic structuring of the species.


Insights from molecular phylogeny

Before molecular data was more readily available, classification systems such as that of Kükenthal placed ''R. alba'' within ''Rhynchospora'' subg. ''Diplostylae'' based on its tubercle and bifid style. How the
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...
Rhynchosporae was related to other groups within the
Cyperaceae The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...
was less clear, with Kükenthal suggesting they formed their own
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
, others suggesting they were part of the larger Cyperaceae tribe Schoenae. A recent
molecular phylogeny Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
suggests that Rhynchosporae are a separate but closely related clade to the Schoenae. Molecular studies within the Rhynchosporae, however, reveal that Kükenthal's widely accepted classification holds less well – neither ''Haplostylae'' nor ''Diplostylae'' are
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 ...
, and there appear to be multiple conversions between bifid and non-bifid styles throughout the genus. Surprisingly, the genus ''Pleurostachys'' (Group I) was also nested within ''Rhynchospora'' rather than sister to it. Further study is required to confirm the position of ''Pleurostachys,'' but this indicates that ''Rhynchospora'' is not monophyletic, and reclassification of both genera may be necessary.


Uses

White beak-sedge is used very little by humans due to its favoured habitat of nutrient-poor acidic bogs, but is sometimes used as an ornamental plant in the UK, and in bog restoration.


Conservation status

''Rhynchospora alba'' is currently assessed by
IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
as
least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
, as it is widespread and "
habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
loss and degradation is not occurring at a scale to qualify the species for a
threatened A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensatio ...
or
near threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...
category". On a regional scale, however, it is threatened by land conversion and over grazing in Central and
Eastern Europe Eastern Europe is a subregion of the Europe, European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural and socio-economic connotations. Its eastern boundary is marked by the Ural Mountain ...
. It is currently threatened in
Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...
,
critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
in
Croatia Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...
and has been reported as
extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
in
Hungary Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...
. There has been little study into the genetic structuring and threat status of the different varieties of ''Rhynchospora alba''. As such, it is not known if regional population declines are eroding genetic and subspecies diversity, nor whether some sections of the species range are of greater conservation concern than others.


References


External links


Jepson Manual TreatmentFlora of North AmericaWashington Burke MuseumPhoto gallery
{{Taxonbar, from=Q1276484
alba ''Alba'' ( , ) is the Scottish Gaelic name for Scotland. It is also, in English-language historiography, used to refer to the polity of Picts and Scots united in the ninth century as the Kingdom of Alba, until it developed into the Kingd ...
Flora of Europe Flora of Northern America Plants described in 1753 Taxa named by Carl Linnaeus