The Polygonaceae are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s known informally as the knotweed family or smartweed—buckwheat family in the United States. The

name A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A personal ...

is based on the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial ...

'' Polygonum'', and was first used by

Antoine Laurent de Jussieu Antoine Laurent de Jussieu (; 12 April 1748 – 17 September 1836) was a French botanist, notable as the first to publish a natural classification of flowering plants; much of his system remains in use today. His classification was based on an e ...

in 1789 in his book, ''Genera Plantarum''.Antoine Laurent de Jussieu. 1789. ''Genera plantarum: secundum ordines naturales disposita, juxta methodum in Horto regio parisiensi exaratam''. page 82. Herrisant and Barrois: Paris, France. (see ''External links'' below) The name may refer to the many swollen nodes the stems of some species have, being derived from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. ** Proto-Greek language, the assumed last common ancestor ...

, ''poly'' meaning 'many' and ''gony'' meaning 'knee' or 'joint'. Alternatively, it may have a different derivation, meaning 'many seeds'. The Polygonaceae comprise about 1200

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate ...

David J. Mabberley. 2008. ''Mabberley's Plant-Book'' third edition (2008). Cambridge University Press: UK. distributed into about 48 genera. The largest genera are '' Eriogonum'' (240 species), '' Rumex'' (200 species), '' Coccoloba'' (120 species), ''

Persicaria ''Persicaria'' is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae. Plants of the genus are known commonly as knotweeds or smartweeds.Calligonum'' (80 species).Craig C. Freeman and James L. Reveal. 2005. "Polygonaceae" pages 216-601. In: Flora of North America Editorial Committee (editors). ''Flora of North America'' vol. 5. Oxford University Press: New York, NY, USA. (see ''External links'' below)John Brandbyge. 1993. "Polygonaceae". pages 531-544. In: Klaus Kubitzki (editor); Jens G. Rohwer, and Volker Bittrich (volume editors). ''The Families and Genera of Vascular Plants'' volume II. Springer-Verlag: Berlin; Heidelberg, Germany (Berlin) (New York) The family is present worldwide, but is most diverse in the North Temperate Zone. Several species are cultivated as ornamentals.

Anthony Huxley Anthony Julian Huxley (2 December 1920 – 26 December 1992) was a British botanist. He edited '' Amateur Gardening'' from 1967 to 1971, and was vice-president of the Royal Horticultural Society in 1991. He was the son of Julian Huxley. He was ...

, Mark Griffiths, and Margot Levy (1992). ''The New Royal Horticultural Society Dictionary of Gardening''. The Macmillan Press,Limited: London. The Stockton Press: New York. (set). A few species of '' Triplaris'' provide

lumber Lumber is wood that has been processed into dimensional lumber, including Beam (structure), beams and plank (wood), planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as fini ...

. The fruit of the sea grape (''

Coccoloba uvifera ''Coccoloba uvifera'' is a species of flowering plant in the buckwheat family, Polygonaceae, that is native to coastal beaches throughout tropical America and the Caribbean, including southern Florida, the Bahamas, the Greater and Lesser Anti ...

'') is eaten, and in

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, jelly is made from it and sold commercially.George W. Staples and Derral R. Herbst "A Tropical Garden Flora" Bishop Museum Press: Honolulu, Hawaii, USA. (2005) The seeds of two species of '' Fagopyrum'', known as

buckwheat Buckwheat (''Fagopyrum esculentum''), or common buckwheat, is a flowering plant in the knotweed family Polygonaceae cultivated for its grain-like seeds and as a cover crop. The name "buckwheat" is used for several other species, such as '' Fagop ...

, are eaten in the form of

groats Groats (or in some cases, "berries") are the hulled kernels of various cereal grains, such as oat, wheat, rye, and barley. Groats are whole grains that include the cereal germ and fiber-rich bran portion of the grain, as well as the endosp ...

or used to make a flour. The petioles of rhubarb ('' Rheum rhabarbarum'' and hybrids) are a food item. The leaves of the common

sorrel Sorrel (''Rumex acetosa''), also called common sorrel or garden sorrel, is a perennial herbaceous plant in the family Polygonaceae. Other names for sorrel include spinach dock and narrow-leaved dock ('dock' being a common name for the genus '' ...

('' Rumex acetosa'') are eaten in

salad A salad is a dish consisting of mixed, mostly natural ingredients with at least one raw ingredient. They are typically served at room temperature or chilled, though some can be served warm. Condiments and salad dressings, which exist in a v ...

s or as a

leaf vegetable Leaf vegetables, also called leafy greens, pot herbs, vegetable greens, or simply greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. Leaf vegetables eaten raw in a salad can be called salad gr ...

.Vernon H. Heywood, Richard K. Brummitt, Ole Seberg, and Alastair Culham. ''Flowering Plant Families of the World''. Firefly Books: Ontario, Canada. (2007). . Polygonaceae contain some of the most prolific weeds, including species of ''Persicaria, Rumex'' and ''Polygonum'', such as Japanese knotweed.

Taxonomy

Polygonaceae are very well-defined and have long been universally recognized. In the

APG III system The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a fur ...

, the family is placed in the order

Caryophyllales Caryophyllales ( ) is a diverse and heterogeneous order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves. The betal ...

. Within the order, it lies outside of the large

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term ...

known as the core Caryophyllales. It is

sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to refer t ...

to the family

Plumbaginaceae Plumbaginaceae is a family of flowering plants, with a cosmopolitan distribution. The family is sometimes referred to as the leadwort family or the plumbago family. Most species in this family are perennial herbaceous plants, but a few grow as ...

, which it does not resemble morphologically.Peter F. Stevens. 2001 onwards. Angiosperm Phylogeny Website At: Missouri Botanical Garden Website. (see ''External links'' below). Polygonum plebeium W IMG 0462

The last comprehensive revision of the family was published in 1993 by John Brandbyge as part of ''The Families and Genera of Vascular Plants''. Brandbyge followed earlier systems of plant classification in dividing Polygonaceae into two

subfamilies In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

, Eriogonoideae and Polygonoideae. Since 1993, the circumscriptions of these two subfamilies have been changed in light of

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

studies of

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. The ...

s. Genera related to ''Coccoloba'' and ''Triplaris'' were moved from Polygonoideae to Eriogonoideae. The genus ''Symmeria'' does not belong to either of these subfamilies because it is sister to the rest of the family. ''Afrobrunnichia'' might constitute a new subfamily as well. Brandbyge wrote descriptions for 43 genera of Polygonaceae in 1993. Since then, a few more genera have been erected, and some segregates of ''Brunnichia'', ''Eriogonum'', and ''Persicaria'' have been given generic

status Status (Latin plural: ''statūs''), is a state, condition, or situation, and may refer to: * Status (law) ** City status ** Legal status, in law ** Political status, in international law ** Small entity status, in patent law ** Status confer ...

in major works.Anjen Li, Bojian Bao, Alisa E. Grabovskaya-Borodina, Suk-pyo Hong, John McNeill, Sergei L. Mosyakin, Hideaki Ohba, and Chong-wook Park. 2003. "Polygonaceae" pages 277-350. In: Zhengyi Wu, Peter H. Raven, and Deyuan Hong (editors). ''Flora of China'' volume 5. Science Press: Beijing, China; Missouri Botanical Garden Press: St. Louis, Missouri, USA. Some of the genera were found not to be

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic grou ...

and their limits have been revised. These include ''Ruprechtia'', ''Eriogonum'', ''Chorizanthe'', ''Persicaria'', ''Aconogonon'', ''Polygonum'', ''Fallopia'', and ''Muehlenbeckia''.

Description

Most Polygonaceae are

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

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 ...

plants with swollen nodes, but

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

s and

vine A vine (Latin ''vīnea'' "grapevine", "vineyard", from ''vīnum'' "wine") is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas or runners. The word ''vine'' can also refer to such stems or runners themselv ...

s are also present. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

of Polygonaceae are simple, and arranged alternately on the stems. Each leaf has a peculiar pair of fused, sheathing

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s known as an ochrea. Those species that do not have the nodal ochrea can be identified by their possession of involucrate

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

s are normally

bisexual Bisexuality is a romantic or sexual attraction or behavior toward both males and females, or to more than one gender. It may also be defined to include romantic or sexual attraction to people regardless of their sex or gender identity, whi ...

, small, and actinomorphic, with a perianth of three to six

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 The term ''sepalum'' was coined ...

s. After flowering, the sepals often become thickened and enlarged around the developing

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in part ...

. Flowers lack a corolla and in some, the sepals are petal-like and colorful. The

androecium The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

is composed of three to eight

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s that are normally free or united at the base. The

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

consists of three united

carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils ...

s that form a single

locule A locule (plural locules) or loculus (plural loculi) (meaning "little place" in Latin) is a small cavity or compartment within an organ or part of an organism (animal, plant, or fungus). In angiosperms (flowering plants), the term ''locule'' usu ...

, which produces only one

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the '' nucellus'' (or remnant of the megasporangium), and the f ...

. The ovary is superior with basal or free-central

placentation Placentation refers to the formation, type and structure, or arrangement of the placenta. The function of placentation is to transfer nutrients, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to remov ...

. The

gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pisti ...

terminates in 1 to 3 styles, each of which ends in a single stigma.Samuel B. Jones and Arlene E. Luchsinger. 1979. ''Plant systematics''. McGraw-Hill series in organismic biology. New York: McGraw-Hill. Page 254. Walter S. Judd, Christopher S. Campbell, Elizabeth A. Kellogg, Peter F. Stevens, and Michael J. Donoghue. 2008. ''Plant Systematics: A Phylogenetic Approach'', Third Edition. Sinauer Associates: Sunderland, MA, USA. Armen L. Takhtajan (Takhtadzhian). ''Flowering Plants'' second edition (2009), pages 155-156. Springer Science+Business Media. . (see ''External links'' below) Persicaria capitata AF crop

Genera

Plants of the World Online Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants b ...

accepted 56 genera: *'' Acanthoscyphus'' Small *'' Afrobrunnichia'' Hutch. & Dalziel *'' Antigonon'' Endl. *'' Aristocapsa'' Reveal & Hardham *'' Atraphaxis'' L. *''

Bactria Bactria (; Bactrian: , ), or Bactriana, was an ancient region in Central Asia in Amu Darya's middle stream, stretching north of the Hindu Kush, west of the Pamirs and south of the Gissar range, covering the northern part of Afghanistan, southwe ...

'' Yurtseva & Mavrodiev *'' Bistorta'' (L.) Scop. *'' Brunnichia'' Banks ex Gaertn. *'' Calligonum'' L. *'' Centrostegia'' A.Gray *'' Chorizanthe'' R.Br. ex Benth. *'' Coccoloba'' P.Browne *'' Dedeckera'' Reveal & J.T.Howell *'' Dodecahema'' Reveal & C.B.Hardham *''

Duma A duma (russian: дума) is a Russian assembly with advisory or legislative functions. The term ''boyar duma'' is used to refer to advisory councils in Russia from the 10th to 17th centuries. Starting in the 18th century, city dumas were fo ...

'' T.M.Schust. *'' Enneatypus'' Herzog *'' Eriogonum'' Michx. *'' Eskemukerjea'' Malick & Sengupta *'' Fagopyrum'' Mill. *''

Fallopia ''Fallopia'' is a genus of about 12 species of flowering plants in the buckwheat family, often included in a wider treatment of the related genus ''Polygonum'' in the past, and previously including ''Reynoutria''. The genus is native to temperat ...

'' Adans. *'' Gilmania'' Coville *'' Goodmania'' Reveal & Ertter *'' Gymnopodium'' Rolfe *'' Harfordia'' Greene & Parry *'' Harpagocarpus'' Hutch. & Dandy *'' Hollisteria'' S.Watson *'' Johanneshowellia'' Reveal *'' Knorringia'' (Czukav.) Tzvelev *'' Koenigia'' L. *'' Lastarriaea'' Remy *'' Leptogonum'' Benth. *'' Magoniella'' Adr.Sanchez *'' Mucronea'' Benth. *'' Muehlenbeckia'' Meisn. *'' Nemacaulis'' Nutt. *'' Neomillspaughia'' S.F.Blake *'' Oxygonum'' Burch. *'' Oxyria'' Hill *'' Oxytheca'' Nutt. *''

Persicaria ''Persicaria'' is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae. Plants of the genus are known commonly as knotweeds or smartweeds.Peutalis'' Raf. *'' Podopterus'' Bonpl. *'' Polygonum'' L. *'' Pteropyrum'' Jaub. & Spach *'' Pterostegia'' Fisch. & C.A.Mey. *'' Pteroxygonum'' Dammer & Diels *'' Reynoutria'' Houtt. *'' Rheum'' L. *'' Rumex'' L. *'' Ruprechtia'' C.A.Mey. *''

Salta Salta () is the capital and largest city in the Argentine province of the same name. With a population of 618,375 according to the 2010 census, it is also the 7th most-populous city in Argentina. The city serves as the cultural and economic c ...

'' Adr.Sanchez *'' Sidotheca'' Reveal *'' Stenogonum'' Nutt. *'' Symmeria'' Benth. *'' Systenotheca'' Reveal & Hardham *'' Triplaris'' Loefl.

Former genera

*''Aconogonon'' (Meisn.) Rchb. – now included in '' Koenigia'' *''Homalocladium'' (F.Muell.) L.H.Bailey – now included in '' Muehlenbeckia'' *''Parapteropyrum'' A.J.Li – now included in '' Fagopyrum'' *''Polygonella'' Michx. – now included in '' Polygonum'' *''Rubrivena'' M.Král – now included in '' Koenigia''

Phylogeny

The following

phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

is based on two papers on the

molecular phylogenetics 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 ...

of Polygonaceae.

Taxonomy

Description

Genera

Former genera

Phylogeny

References

External links