Polygonaceae | |
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Persicaria maculosa | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Caryophyllales |
Family: | Polygonaceae Juss. [1] |
Subfamilies | |
The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus Polygonum , and was first used by Antoine Laurent de Jussieu in 1789 in his book, Genera Plantarum. [2] The name may refer to the many swollen nodes the stems of some species have, being derived from Greek [poly meaning 'many' and gony meaning 'knee' or 'joint']. Alternatively, it may have a different origin, meaning 'many seeds'. [3]
The Polygonaceae comprise about 1200 species [4] distributed into about 48 genera. [5] The largest genera are Eriogonum (240 species), Rumex (200 species), Coccoloba (120 species), Persicaria (100 species) and Calligonum (80 species). [6] [7] The family is present worldwide, but is most diverse in the North Temperate Zone.
Several species are cultivated as ornamentals. [8] A few species of Triplaris provide lumber. [4] The fruit of the sea grape ( Coccoloba uvifera ) is eaten, and in Florida, jelly is made from it and sold commercially. [9] The seeds of two species of Fagopyrum , known as buckwheat, are eaten in the form of groats or used to make flour. The petioles of rhubarb ( Rheum rhabarbarum and hybrids) are a food item. The leaves of the common sorrel ( Rumex acetosa ) are eaten in salads or as a leaf vegetable. [10]
Polygonaceae contain some of the most prolific weeds, including species of Persicaria, Rumex and Polygonum, as well as Japanese knotweed. [4]
Polygonaceae are very well-defined and have long been universally recognized. In the APG III system, the family is placed in the order Caryophyllales. [1] Within the order, it lies outside of the large clade known as the core Caryophyllales. [11] It is a sister to the family Plumbaginaceae, which it does not resemble morphologically. [12]
The last comprehensive revision of the family was published in 1993 by John Brandbyge as part of The Families and Genera of Vascular Plants. [7] Brandbyge followed earlier systems of plant classification in dividing Polygonaceae into two subfamilies, Eriogonoideae and Polygonoideae. Since 1993, the circumscriptions of these two subfamilies have been changed in light of phylogenetic studies of DNA sequences. [13] 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 a sister to the rest of the family. [14] Afrobrunnichia might constitute a new subfamily as well. [15]
Brandbyge wrote descriptions for 43 genera of Polygonaceae in 1993. [7] Since then, a few more genera have been erected, and some segregates of Brunnichia, Eriogonum, and Persicaria have been given generic status in major works. [6] [14] [16] Some of the genera were found not to be monophyletic and their limits have been revised. These include Ruprechtia, Eriogonum, Chorizanthe, Persicaria, Aconogonon, Polygonum, Fallopia, and Muehlenbeckia.
Most Polygonaceae are perennial herbaceous plants with swollen nodes, but trees, shrubs and vines are also present. The leaves of Polygonaceae are simple, and arranged alternately on the stems. Each leaf has a peculiar pair of fused, sheathing stipules, known as an ochrea. Those species that do not have the nodal ochrea can be identified by their possession of involucrate flower heads. The flowers are normally bisexual, small, and actinomorphic, with a perianth of three to six sepals. After flowering, the sepals often become thickened and enlarged around the developing fruit. Flowers lack a corolla and in some, the sepals are petal-like and colorful. The androecium is composed of three to eight stamens that are normally free or united at the base. The ovary consists of three united carpels that form a single locule, which produces only one ovule. The ovary is superior with basal or free-central placentation. The gynoecium terminates in 1 to 3 styles, each of which ends in a single stigma. [17] [18] [19]
As of March 2019 [update] , Plants of the World Online accepted 56 genera: [20]
The following phylogenetic tree is based on two papers on the molecular phylogenetics of Polygonaceae. [13] [14]
Polygonaceae |
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Bistorta officinalis, known as bistort, common bistort, European bistort, or meadow bistort, is a species of flowering plant in the dock family Polygonaceae native to Europe and northern and western Asia. Other common names include snakeroot, snake-root, snakeweed, and Easter-ledges.
Persicaria is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae. Plants of the genus are known commonly as knotweeds or smartweeds. It has a cosmopolitan distribution, with species occurring nearly worldwide. The genus was segregated from Polygonum.
Polygonum is a genus of about 130 species of flowering plants in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass. In the Middle English glossary of herbs Alphita, it was known as ars-smerte. There have been various opinions about how broadly the genus should be defined. For example, buckwheat has sometimes been included in the genus as Polygonum fagopyrum. Former genera such as Polygonella have been subsumed into Polygonum; other genera have been split off.
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 temperate and subtropical regions of the Northern Hemisphere, but species have been introduced elsewhere. The genus includes species forming vines and shrubs.
Muehlenbeckia or maidenhair is a genus of flowering plants in the family Polygonaceae. It is native to the borders of the Pacific, including South and North America, Papua New Guinea and Australasia. It has been introduced elsewhere, including Europe. Species vary in their growth habits, many being vines or shrubs. In some environments, rampant species can become weedy and difficult to eradicate.
James Lauritz Reveal was a U.S. botanist best known for his contributions to the genus Eriogonum and for his work on suprageneric names. His website, at PlantSystematics.org, also presents material on plant taxonomy including the Reveal system. He published extensively on North American flora, was a member of the Angiosperm Phylogeny Group, and was one of the authors of the APG II and APG III classifications.
Koenigia is a genus of plants in the family Polygonaceae. The genus Aconogonon has been merged into Koenigia.
Atraphaxis is a genus of flowering plants in the family Polygonaceae with about 40 species.
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 betalain pigments are unique in plants of this order and occur in all its families with the exception of Caryophyllaceae and Molluginaceae.
Bistorta is a genus of flowering plants in the family Polygonaceae. As of February 2019 about 40 species are accepted. It has been supported as a separate clade by molecular phylogenetic analysis. Bistorta species are native throughout much of the Northern Hemisphere, as far south as Mexico in North America and Thailand in Asia.
Polygonum dentoceras is a rare species of flowering plant in the knotweed family known by the common names sandlace, woody wireweed, and Small's jointweed. It is endemic to Florida in the United States, where it is limited to the central ridges of the peninsula, including the Lake Wales Ridge. It is threatened by the loss and degradation of its habitat. It is a federally listed endangered species of the United States.
Polygonum smallianum is a species of flowering plant in the knotweed family known by the common name largeleaf jointweed. It is native to a small area around the border between Alabama and Florida in the United States.
Polygonum delopyrum, the fringed jointweed or hairy jointweed, is a plant species endemic to Florida. It is found in pinelands and sandy pine barrens at elevations less than 50 m, in central and southern parts of the state.
Polygonum americanum, commonly called southern jointweed or American jointweed, is a species of flowering plant in the knotweed family. It is native to Southeastern United States extending in scattered locations west to New Mexico. Its preferred habitat is dry, sandy areas.
Reynoutria is a genus of flowering plants in the Polygonaceae, also known as the knotweed or buckwheat family. The genus is native to eastern China, Eastern Asia and the Russian Far East, although species have been introduced to Europe and North America. Members of the genus, including R. japonica and its hybrid with R. sachalinensis, are highly invasive plants.
Polygonoideae is a subfamily of plants in the family Polygonaceae. It includes a number of plants that can be highly invasive, such as Japanese knotweed, Reynoutria japonica, and its hybrid with R. sachalinensis, R. × bohemica. Boundaries between the genera placed in the subfamily and their relationships have long been problematic, but a series of molecular phylogenetic studies have clarified some of them, resulting in the division of the subfamily into seven tribes.
Duma is a genus of shrubby flowering plants in the family Polygonaceae, subfamily Polygonoideae. The genus was separated from Muehlenbeckia in 2011. The native range of the genus is Australia.
Polygonum ciliinode is a species of flowering plant in the family Polygonaceae, native to central and eastern Canada, and the north-central and eastern United States. The specific epithet is also spelt cilinode.
Tanja Magdalena Schuster is a taxonomist from Austria, and the first Pauline Ladiges Plant Systematics Fellow, holding a joint position with the School of Biosciences, University of Melbourne, Victoria, Australia, and the National Herbarium of Victoria, Royal Botanic Gardens Melbourne. Schuster also worked as curator of the Norton-Brown Herbarium at the University of Maryland, College Park.
Koenigia × fennica, known as Finnish knotweed, is a hybrid between two species of Koenigia, K. alpina and K. weyrichii, members of the family Polygonaceae, the knotweed family. It generally only known as a cultivated garden plant, but plants have been recorded a few times surviving in abandoned areas in northern Europe, especially in Finland. The cultivar 'Johanniswolke' is considered an attractive ornamental perennial plant.