Diapensiaceae | |
---|---|
Diapensia lapponica | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Ericales |
Family: | Diapensiaceae Lindl. [1] |
Diapensiaceae is a small family of flowering plants, which includes 15 species in 6 genera. [2] The genera include Berneuxia Decne. (1 species), [3] Diapensia L. (5 species), [4] Galax Sims (1 species), [3] Pyxidanthera Michx. (2 species), [5] Shortia Torr. & A.Gray (4 species), [6] and Schizocodon Siebold & Zucc. (2 species). [6] Members of this family have little economic importance; however, some members are cultivated by florists. [7]
Past literature classified Diapensiaceae as an old family, without defining the meaning of old. [8] The name Diapensia was given to Diapensia lapponica by Linnaeus. Previously, it was the Greek name of sanicle. [9] [10] The family, originally including only Diapensia lapponica, was named by Heinrich Friedrich Link in 1829. [11] Concerning the interrelationships in Diapensiaceae, debate still remains regarding the recognition of Schizocodon and whether it should be separate from Shortia. However, recent molecular studies support the split of the two genera. [6] Additionally, recognition of species within the genera has been debated. Within the genus Pyxidanthera, two species have previously been recognized. Recent morphology and molecular work found that the two species do not differ morphologically, gene flow exists between them, and the taxa are not monophyletic. [12] [13]
Over time, various relationships among Diapensiaceae and other angiosperm families have been proposed. Previously, it was placed within the order Rosales, [14] as well as in the Cornales. [15] Diapensiaceae was also placed in an order of its own in the Cronquist system and by Takhtajan. [16] Recent studies have placed Diapensiaceae as part of the Ericales clade, belonging to the “styracoids” (Diapensiaceae, Styracaceae, Symplocaceae). [17] It is estimated that Diapensiaceae diverged from Sytracaceae about 93 million years ago. [18] The family is thought to have originated in the Northern Hemisphere. [19]
Family Diapensiaceae members are mostly found in North America and Eastern Asia. [7]
Genera | Distribution [20] |
---|---|
Berneuxia | Tibet, southern China, and Burma |
Diapensia | Mostly mountains in southern Asia, Diapensia lapponica is circumboreal |
Galax | Eastern United States |
Pyxidanthera | Eastern United States |
Shortia | Eastern United States, China, and Taiwan |
Schizocodon | Japan |
Members of Diapensiaceae are mostly herbs or shrublets. Flowers have radial symmetry, are hypogynous, and have most parts arranged in whorls of 5. The ovary is made of three fused carpels. They have both ectotrophic and endotrophic mycorrhiza associations. [3]
Genera | Life form | Leaf shape | Inflorescence characters |
---|---|---|---|
Berneuxia | Perennial herb | linear and petiolate | Distinct scape |
Diapensia | Cushion-like shrublet | linear and lanceolate to oblanceolate and sessile | Solitary |
Galax | Perennial herb | reniform to orbicular and petiolate | Raceme |
Pyxidanthera | Cushion-like shrublet | linear and lanceolate to oblanceolate and sessile | Solitary |
Shortia/Schizocodon | Perennial herb | reniform to orbicular and petiolate | Solitary or raceme |
The Ericales are a large and diverse order of dicotyledons. Species in this order have considerable commercial importance including for tea, persimmon, blueberry, kiwifruit, Brazil nuts, argan, and azalea. The order includes trees, bushes, lianas, and herbaceous plants. Together with ordinary autophytic plants, the Ericales include chlorophyll-deficient mycoheterotrophic plants and carnivorous plants.
The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae. It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants. At least 10 morphological characters unite the Nymphaeales. One of the traits is the absence of a vascular cambium, which is required to produce both xylem (wood) and phloem, which therefore are missing. Molecular synapomorphies are also known.
The Actinidiaceae are a small family of flowering plants. The family has three genera and about 360 species and is a member of the order Ericales.
Betulaceae, the birch family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeam, and hop-hornbeams numbering a total of 167 species. They are mostly natives of the temperate Northern Hemisphere, with a few species reaching the Southern Hemisphere in the Andes in South America. Their typical flowers are catkins and often appear before leaves.
Geraniales is a small order of flowering plants, included within the rosid subclade of eudicots. The largest family in the order is Geraniaceae with over 800 species. In addition, the order includes the smaller Francoaceae with about 40 species. Most Geraniales are herbaceous, but there are also shrubs and small trees.
The Ulmaceae are a family of flowering plants that includes the elms, and the zelkovas. Members of the family are widely distributed throughout the north temperate zone, and have a scattered distribution elsewhere except for Australasia.
Hamamelidaceae, commonly referred to as the witch-hazel family, is a family of flowering plants in the order Saxifragales. The clade consists of shrubs and small trees positioned within the woody clade of the core Saxifragales. An earlier system, the Cronquist system, recognized Hamamelidaceae in the Hamamelidales order.
The Primulaceae, commonly known as the primrose family, are a family of herbaceous and woody flowering plants including some favourite garden plants and wildflowers. Most are perennial though some species, such as scarlet pimpernel, are annuals.
Winteraceae is a primitive family of tropical trees and shrubs including 93 species in five genera. It is of particular interest because it is such a primitive angiosperm family, distantly related to Magnoliaceae, though it has a much more southern distribution. Plants in this family grow mostly in the southern hemisphere, and have been found in tropical to temperate climate regions of Malesia, Oceania, eastern Australia, New Zealand, Madagascar and the Neotropics, with most of the genera concentrated in Australasia and Malesia. The five genera, Takhtajania, Tasmannia, Drimys, Pseudowintera, and Zygogynum s.l. all have distinct geographic extant populations. Takhtajania includes a single species, T. perrieri, endemic only to Madagascar, Tasmannia has the largest distribution of genera in Winteraceae with species across the Philippines, Borneo, New Guinea, Eastern Australia, and Tasmannia, Drimys is found in the Neotropical realm, from southern Mexico to the subarctic forests of southern South America, Pseudowintera is found only in New Zealand, and Zygogynum has species in New Guinea and New Caledonia.
Lentibulariaceae is a family of carnivorous plants containing three genera: Genlisea, the corkscrew plants; Pinguicula, the butterworts; and Utricularia, the bladderworts.
The Crypteroniaceae are a family of flowering trees and shrubs. The family includes 13 species in three genera, native to Indomalaya.
Cunoniaceae is a family of 27 genera and about 335 species of woody plants in the order Oxalidales, mostly found in the tropical and wet temperate regions of the Southern Hemisphere. The greatest diversity of genera are in Australia and Tasmania, New Guinea, and New Caledonia. The family is also present in Central America, South America, the Caribbean, Malesia, the islands of the South Pacific, Madagascar and surrounding islands. the family is absent from mainland Asia except from Peninsular Malaysia, and almost absent from mainland Africa apart from two species from Southern Africa. Several of the genera have remarkable disjunct ranges, found on more than one continent, e.g. Cunonia, EucryphiaWeinmannia.
The Clethraceae are a small family of flowering plants in the order Ericales, composed of two genera, Clethra and Purdiaea, with approximately 75 species. They are native to warm temperate to tropical regions of Asia and the Americas, with one species also on Madeira.
Begoniaceae is a family of flowering plants with two genera and about 2040 species occurring in the subtropics and tropics of both the New World and Old World. All but one of the species are in the genus Begonia. There have been many recent discoveries of species in the genus Begonia, such as Begonia truncatifolia which is endemic to San Vincente, Palawan. B. truncatifolia is smaller in size than other species of the genus Begonia and this new species is proposed Critically Endangered by standards set by the IUCN. The only other genus in the family, Hillebrandia, is endemic to the Hawaiian Islands and has a single species. Phylogenetic work supports Hillebrandia as the sister taxon to the rest of the family. The genus Symbegonia was reduced to a section of Begonia in 2003, as molecular phylogenies had shown it to be derived from within that genus. Members of the genus Begonia are well-known and popular houseplants.
Theophrastoideae is a small subfamily of flowering plants in the family Primulaceae. It was formerly recognized as a separate family Theophrastaceae. As previously circumscribed, the family consisted of eight genera and 95 species of trees or shrubs, native to tropical regions of the Americas.
The Rafflesiaceae are a family of rare parasitic plants comprising 36 species in 3 genera found in the tropical forests of east and southeast Asia, including Rafflesia arnoldii, which has the largest flowers of all plants. The plants are endoparasites of vines in the genus Tetrastigma (Vitaceae) and lack stems, leaves, roots, and any photosynthetic tissue. They rely entirely on their host plants for both water and nutrients, and only then emerge as flowers from the roots or lower stems of the host plants.
Sladeniaceae is a family of flowering plants containing tree species found in subtropical to tropical environments in East Africa (Ficalhoa), Burma, Yunnan, and Thailand (Sladenia). The family consists of trees with alternate, simple leaves without stipules, and flowers arranged in cymose inflorescences.
When the APG II system of plant classification was published in April 2003, fifteen genera and three families were placed incertae sedis in the angiosperms, and were listed in a section of the appendix entitled "Taxa of uncertain position".
Hydrostachys is a genus of about 22 species of flowering plants native to Madagascar and southern and central Africa. It is the only genus in the family Hydrostachyaceae. All species of Hydrostachys are aquatic, growing on rocks in fast-moving water. They have tuberous roots, usually pinnately compound leaves, and highly reduced flowers on dense spikes.
The taxonomy of the plant family Liliaceae has had a complex history since its first description in the mid-eighteenth century. Originally, the Liliaceae were defined as having a "calix" (perianth) of six equal-coloured parts, six stamens, a single style, and a superior, three-chambered (trilocular) ovary turning into a capsule fruit at maturity. The taxonomic circumscription of the family Liliaceae progressively expanded until it became the largest plant family and also extremely diverse, being somewhat arbitrarily defined as all species of plants with six tepals and a superior ovary. It eventually came to encompass about 300 genera and 4,500 species, and was thus a "catch-all" and hence paraphyletic. Only since the more modern taxonomic systems developed by the Angiosperm Phylogeny Group (APG) and based on phylogenetic principles, has it been possible to identify the many separate taxonomic groupings within the original family and redistribute them, leaving a relatively small core as the modern family Liliaceae, with fifteen genera and 600 species.
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