|
Dryadoideae
The subfamily Dryadoideae consists of four genera in the family Rosaceae,. all of which contain representative species with root nodules that host the nitrogen-fixing bacterium ''Frankia''. They are subshrubs, shrubs, or small trees with a base chromosome number of 9, whose fruits are either an achene or an aggregate of achenes. It includes five genera ('' Dryas'', ''Cercocarpus'', '' Chamaebatia'', '' Cowania'', and ''Purshia ''Purshia'' (bitterbrush or cliff-rose) is a small genus of 5–8 species of flowering plants in the family Rosaceae which are native to western North America. Description ''Purshia'' species form deciduous or evergreen shrubs, typically reach ...''), all of which except the first only occur in North America. Taxonomic history The subfamily has at various times been separated as its own family (Dryadaceae), or as a tribe (Dryadeae) or subtribe (Dryadinae). References External links * * Rosid subfamilies {{rosaceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosaceae
Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus '' Rosa''. The family includes herbs, shrubs, and trees. Most species are deciduous, but some are evergreen. They have a worldwide range but are most diverse in the Northern Hemisphere. Many economically important products come from the Rosaceae, including various edible fruits, such as apples, pears, quinces, apricots, plums, cherries, peaches, raspberries, blackberries, loquats, strawberries, rose hips, hawthorns, and almonds. The family also includes popular ornamental trees and shrubs, such as roses, meadowsweets, rowans, firethorns, and photinias. Among the most species-rich genera in the family are '' Alchemilla'' (270), '' Sorbus'' (260), ''Crataegus'' (260), '' Cotoneaster'' (260), '' Rubus'' (250), and ''Prunus'' (200), which contains the plums, cherries, peaches, apricots, and almonds. However, all of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryadoideae
The subfamily Dryadoideae consists of four genera in the family Rosaceae,. all of which contain representative species with root nodules that host the nitrogen-fixing bacterium ''Frankia''. They are subshrubs, shrubs, or small trees with a base chromosome number of 9, whose fruits are either an achene or an aggregate of achenes. It includes five genera ('' Dryas'', ''Cercocarpus'', '' Chamaebatia'', '' Cowania'', and ''Purshia ''Purshia'' (bitterbrush or cliff-rose) is a small genus of 5–8 species of flowering plants in the family Rosaceae which are native to western North America. Description ''Purshia'' species form deciduous or evergreen shrubs, typically reach ...''), all of which except the first only occur in North America. Taxonomic history The subfamily has at various times been separated as its own family (Dryadaceae), or as a tribe (Dryadeae) or subtribe (Dryadinae). References External links * * Rosid subfamilies {{rosaceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryas (plant)
''Dryas'' is a genus of perennial cushion-forming evergreen dwarf shrubs in the family Rosaceae, native to the arctic and alpine regions of Europe, Asia and North America. The genus is named after the dryads, the tree nymphs of ancient Greek mythology. The classification of ''Dryas'' within the Rosaceae has been unclear. The genus was formerly placed in the subfamily Rosoideae, but is now placed in subfamily Dryadoideae. The species are superficially similar to '' Geum'' (with which they share the common name avens), ''Potentilla'', and ''Fragaria'' (strawberry). However, ''Dryas'' are distinct in having flowers with ''eight'' petals (rarely seven or up to ten), instead of the five petals found in most other genera in the Rosaceae. The flowers are erect and white with a yellow centre ('' Dryas integrifolia'', ''Dryas octopetala'') or pendulous and all-yellow ('' Dryas drummondii''), and held conspicuously above the small plants. This makes them very popular in rockeries and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cowania (plant)
''Purshia'' (bitterbrush or cliff-rose) is a small genus of 5–8 species of flowering plants in the family Rosaceae which are native to western North America. Description ''Purshia'' species form deciduous or evergreen shrubs, typically reaching tall. The leaves are long, deeply three- to five-lobed, with revolute margins. The flowers are 1–2 cm in diameter, with five white to pale yellow or pink petals and yellow stamens. The fruit is a cluster of dry, slender, leathery achenes which are 2–6 cm long. The roots have nodules that host nitrogen-fixing ''Frankia'' bacterium. Taxonomy Taxonomic history The genus was originally placed in the subfamily Rosoideae. In the past, the evergreen species were treated separately in the genus ''Cowania''; this genus is still accepted by some botanists. Modern classification The classification of ''Purshia'' within the family Rosaceae has been unclear. It is now placed in the subfamily Dryadoideae. Species ''Purshia'' compr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercocarpus
''Cercocarpus'', commonly known as mountain mahogany, is a small genus of at least nine species of nitrogen-fixing flowering plants in the rose family, Rosaceae. They are native to the western United States and northern Mexico, where they grow in chaparral and semidesert habitats and climates, often at high altitudes. Several are found in the California chaparral and woodlands ecoregion. The classification of ''Cercocarpus'' within the Rosaceae has been unclear. The genus has been placed in the subfamily Rosoideae, but is now placed in subfamily Dryadoideae. Members of the genus are deciduous shrubs or small trees, typically reaching heights of 3–6 m (9–18 ft) tall, but exceptionally up to 13 m (40 ft) high. '' C. montanus'' usually remains under 1 m (3 ft) high because of incessant grazing by elk and deer. The name is derived from the Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Gree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamaebatia
''Chamaebatia'', also known as mountain misery, is a genus of two species of aromatic evergreen shrubs endemic to California. Its English common name derives from early settlers' experience with the plant's dense tangle and sticky, strong-smelling resin. They are actinorhizal, non-legumes capable of nitrogen fixation through symbiosis with the actinobacterium, ''Frankia ''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the '' Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of ro ...''. Taxonomy Species ''Chamaebatia'' comprises the following species: * '' Chamaebatia australis'' (Brandegee) Abrams – Southern mountain misery * '' Chamaebatia foliolosa'' Benth. – Sierra mountain misery, bearclover, kit-kit-dizze Species names with uncertain taxonomic status The status of the following species is unresolved: * ''Chamaebatia foliolosa'' Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purshia
''Purshia'' (bitterbrush or cliff-rose) is a small genus of 5–8 species of flowering plants in the family Rosaceae which are native to western North America. Description ''Purshia'' species form deciduous or evergreen shrubs, typically reaching tall. The leaves are long, deeply three- to five-lobed, with revolute margins. The flowers are 1–2 cm in diameter, with five white to pale yellow or pink petals and yellow stamens. The fruit is a cluster of dry, slender, leathery achenes which are 2–6 cm long. The roots have nodules that host nitrogen-fixing ''Frankia'' bacterium. Taxonomy Taxonomic history The genus was originally placed in the subfamily Rosoideae. In the past, the evergreen species were treated separately in the genus ''Cowania''; this genus is still accepted by some botanists. Modern classification The classification of ''Purshia'' within the family Rosaceae has been unclear. It is now placed in the subfamily Dryadoideae. Species ''Purshia'' compr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Fixation
Nitrogen fixation is a chemical process by which molecular dinitrogen () is converted into ammonia (). It occurs both biologically and abiological nitrogen fixation, abiologically in chemical industry, chemical industries. Biological nitrogen fixation or ''diazotrophy'' is catalyzed by enzymes called nitrogenases. These enzyme complexes are encoded by the Nif gene, ''Nif'' genes (or ''Nif'' homologs) and contain iron, often with a second metal (usually molybdenum, but sometimes vanadium). Some nitrogen-fixing bacteria have symbiotic relationships with plants, especially legumes, mosses and aquatic ferns such as ''Azolla''. Looser non-symbiotic relationships between diazotrophs and plants are often referred to as associative, as seen in nitrogen fixation on rice roots. Nitrogen fixation occurs between some termites and fungus, fungi. It occurs naturally in the air by means of NOx, NOx production by lightning. Fixed nitrogen is essential to life on Earth. Organic compounds such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Fruit
The term compound fruit is not used in technical botanical writing, but is sometimes used when it is not clear which of several fruit types is involved. A compound fruit is "composed of two or more similar parts". A compound fruit may be: * An aggregate fruit, in which one flower contains several separate ovaries, which merge during development. * A multiple fruit, in which several flowers, each with an ovary, develop into small fruits that are clustered or fused together into a larger fruit. * A simple fruit formed from a compound ovary. Image:Frambozenkever.jpg, A raspberry is an aggregate fruit (shown with a raspberry beetle larva) Image:Pineapple 'Victoria' with slice.jpg, A pineapple is a multiple fruit Image:Kumato 02.jpg, A tomato is a simple fruit derived from a compound ovary Grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Dehiscence (botany), indehiscent (they do not open at maturity). Achenes contain a single seed that nearly fills the pericarp, but does not adhere to it. In many species, what is called the "seed" is an achene, a fruit containing the seed. The seed-like appearance is owed to the hardening of the fruit wall (pericarp), which encloses the solitary seed so closely as to seem like a seed coat. Examples The fruits of buttercup, buckwheat, caraway, quinoa, amaranth, and cannabis are typical achenes. The achenes of the strawberry are sometimes mistaken for seeds. The strawberry is an accessory fruit with an aggregate of achenes on its outer surface, and what is eaten is accessory tissue. A rose produces an aggregate of achene fruits that are encom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most important of these proteins are the histones. Aided by chaperone proteins, the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. Normally, chromosomes are visible under a light microscope only during the metaphase of cell division, where all chromosomes are aligned in the center of the cell in their condensed form. Before this stage occurs, each chromosome is duplicated ( S phase), and the two copies are joined by a centromere—resulting in either an X-shaped structure if the centromere is located equatorially, or a two-armed structure if the centromere is located distally; the jo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frankia
''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the '' Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of root nodules. This genus was originally named by Jørgen Brunchorst, in 1886 to honor the German biologist Albert Bernhard Frank. Brunchorst considered the organism he had identified to be a filamentous fungus. redefined the genus in 1970 as containing prokaryotic actinomycetes and created the family Frankiaceae within the Actinomycetales. He retained the original name of ''Frankia'' for the genus. __TOC__ Overview Most ''Frankia'' strains are specific to different plant species. The bacteria are filamentous and convert atmospheric nitrogen into ammonia via the enzyme nitrogenase, a process known as nitrogen fixation. They do this while living in root nodules on actinorhizal plants. The bacteria can supply most or all of the nit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
