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Argyroxiphium
''Argyroxiphium'' is a small genus of plants in the family Asteraceae. Its members are known by the common names silversword or greensword due to their long, narrow leaves and the silvery hairs on some species. The silverswords belong to a larger radiation of over 50 species, including the physically different genera '' Dubautia'' and '' Wilkesia''. This grouping is often referred to as the silversword alliance. . Baldwin. Age and Rate of Diversification of the Hawaiian Silversword Alliance (Compositae). 1998./ref> Botanist P. H. Raven referred to this radiation as "the best example of adaptive radiation in plants". Description Species in ''Argyroxiphium'' are perennial, rosette-forming shrubs. They may consist of a single large rosette or a collection of several rosettes. In all ''Argyroxiphium'' species, long, narrow leaves contain interstitial gels hypothesized to function as water storage. For some species, leaves are covered with trichomes that provide protection from f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haleakalā Silversword
''Argyroxiphium sandwicense'' subsp. ''macrocephalum'', the east Maui silversword or Haleakalā silversword, is a rare plant, part of the family Asteraceae. The silversword in general is referred to as ''āhinahina'' in Hawaiian (literally, "very gray"). Distribution The Haleakalā silversword is found on the island of Maui at elevations above on the dormant Haleakalā volcanoon the summit depression, the rim summits, and surrounding slopesin Haleakalā National Park. The Haleakalā silversword has been a threatened species as defined by the U.S. Fish and Wildlife Service, since May 15, 1992. Prior to that time, excessive grazing by cattle and goats, and vandalism inflicted by people in the 1920s, had caused its near extinction. Since strict monitoring and governmental protection took effect, the species' recovery is considered a successful conservation story, although threats remain. Description The Haleakalā silversword, ''Argyroxiphium sandwicense'' subsp. ''macrocephalu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silversword Alliance
The silversword alliance, also known as the tarweeds, refers to an adaptive radiation of around 30 species in the composite or sunflower family, Asteraceae. The group is Endemism, endemic to Hawaii, and is derived from a single immigrant to the islands. For radiating from a common ancestor at an estimated 5.2±0.8 Ma, the clade is extremely diverse, composed of trees, shrubs, subshrubs, mat-plants, cushion plants, Rosette (botany), rosette plants, and lianas. The silversword alliance is named for its most famous and visually striking members, the Argyroxiphium, silverswords. The species of the clade break down into three genera: ''Wilkesia, Argyroxiphium,'' and ''Dubautia.'' There are three species of silverswords and two greenswords in the genus ''Argyroxiphium'', confined to the islands of Maui and Hawaii (island), Hawaii, and two species of ''Wilkesia'' (''iliau'') on Kauai, Kauai. The bulk of the species are placed in the genus ''Dubautia'', which is widespread on all the main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Radiation
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. Starting with a single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos ("Darwin's finches"), but examples are known from around the world. Characteristics Four features can be used to identify an adaptive radiation: #A common ancestry of component species: specifically a ''recent'' ancestry. Note that this is not the same as a monophyly in which ''all'' descendants of a common ancestor are included. #A phenotype-environment correlation: a ''significant'' association between environments and the mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madieae
Madieae is a tribe of flowering plants in the family Asteraceae. It is sometimes considered a subtribe of Heliantheae. Notable species include the tarweeds of the Western United States as well as the silverswords of Hawaii. Subtribes and genera Madieae subtribes and genera recognized by the Global Compositae Database as of April 2022: *Subtribe Arnicinae **''Arnica'' *Subtribe Baeriinae **''Amblyopappus'' **'' Baeriopsis'' **'' Constancea'' **'' Eriophyllum'' **'' Lasthenia'' **'' Monolopia'' **'' Pseudobahia'' **'' Syntrichopappus'' *Subtribe Hulseinae **'' Eatonella'' **'' Hulsea'' *Subtribe Madiinae **'' Achyrachaena'' **'' Adenothamnus'' **'' Anisocarpus'' **'' Argyroxiphium'' **'' Blepharipappus'' **'' Blepharizonia'' **'' Calycadenia'' **''Carlquistia'' **'' Centromadia'' **'' Deinandra'' **'' Dubautia'' **''Harmonia In Greek mythology, Harmonia (; /Ancient Greek phonology, harmoˈnia/, "harmony", "agreement") is the goddess of harmony ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilkesia
''Wilkesia'' is a genus of Hawaiian plants in the tribe Madieae within the family Asteraceae. It contains two perennials, both of which are endemic to the island of Kauai in Hawaii. ''Wilkesia'' is a component of the silversword alliance and is named after Captain Charles Wilkes. ;Species * '' Wilkesia gymnoxiphium'' A.Gray, 1852 * '' Wilkesia hobdyi'' H.St.John, 1971 ;formerly included ''Wilkesia grayana - Argyroxiphium grayanum ''Argyroxiphium grayanum'', commonly known as the greensword, is a species of flowering plant in the family Asteraceae, and a member of the silversword alliance, a group of over 50 species which are diverse in morphology and habitat but are gen ...'' References External links * Madieae Endemic flora of Hawaii Biota of Kauai Asteraceae genera Taxa named by Asa Gray {{Madieae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocarpic
Monocarpic plants are those that flower and set seeds only once, and then die. The term is derived from Greek (', "single" + , "fruit" or "grain"), and was first used by Alphonse de Candolle. Other terms with the same meaning are '' hapaxanth'' and ''semelparous''. The antonym is polycarpic, a plant that flowers and sets seeds many times during its lifetime; the antonym of semelparous is ''iteroparous''. Plants which flower en masse (gregariously) before dying are known as plietesials. The term ''hapaxanth'' is most often in conjunction with describing some of the taxa of Arecaceae (palms) and some species of bamboo, but rarely used otherwise; its antonym is ''pleonanth''. This was first used by Alexander Braun. Monocarpic plants are not necessarily annuals, because some monocarpic plants can live a number of years before they will flower. In some monocarpic plants, flowering signals senescence, while in others the production of fruits and seeds causes changes within the plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollinator
A pollinator is an animal that moves pollen from the male anther of a flower to the female carpel, stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the major pollinators of most plants, and insect pollinators include all families of bees and most families of Aculeata, aculeate wasps; ants; many families of flies; many lepidopterans (both butterflies and moths); and many families of beetles. Vertebrates, mainly bats and birds, but also some non-bat mammals (monkeys, lemurs, Phalangeriformes, possums, rodents) and some lizards pollinate certain plants. Among the pollinating birds are hummingbirds, honeyeaters and sunbirds with long beaks; they pollinate a number of deep-throated flowers. Humans may also carry out artificial pollination. A pollinator is different from a pollenizer, a plant that is a source of pollen for the pollination process. Background Plants fall into pollination s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed
In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilization, fertilized by Pollen, sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted. The formation of the seed is the defining part of the process of reproduction in seed plants (spermatophytes). Other plants such as ferns, mosses and marchantiophyta, liverworts, do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological Ecological niche, niches on land, from forests to grasslands both in hot and cold climates. In the flowering plants, the ovary ripens into a fruit which contains the seed and serves to disseminate ... [...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] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridization, which include genetic and morph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed Dispersal
In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, such as the wind, and living (Biotic component, biotic) vectors such as birds. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. The patterns of seed dispersal are determined in large part by the dispersal mechanism and this has important implications for the demographic and genetic structure of plant populations, as well as wikt:migration, migration patterns and species interactions. There are five main modes of seed dispersal: Gravitation, gravity, wind, ballistic, water, and by animals. Some plants are serotinous and only disperse their seeds in response to an environmental stimulus. These modes are typically inferred based on adaptations, such as wings or fle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population, or a species (extinct or Extant taxon, extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed ''monophyletic'' (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming Taxon, taxa that are not clades; that is, taxa that are not Monophyly, monophyletic. Some of the relationships between organisms that the molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
