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Haleakala 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] |
Asa Gray
Asa Gray (November 18, 1810 – January 30, 1888) is considered the most important American botany, botanist of the 19th century. His ''Darwiniana'' (1876) was considered an important explanation of how religion and science were not necessarily mutually exclusive. Gray was adamant that a genetic connection must exist between all members of a species. He was also strongly opposed to the ideas of hybridization within one generation and special creation in the sense of its not allowing for evolution. He was a strong supporter of Darwin, although Gray's theistic evolution was guided by a Creator. As a professor of botany at Harvard University for several decades, Gray regularly visited, and corresponded with, many of the leading natural scientists of the era, including Charles Darwin, who held great regard for him. Gray made several trips to Europe to collaborate with leading European scientists of the era, as well as trips to the southern and western United States. He also built a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauna Kea
Mauna Kea (, ; abbreviation for ''Mauna a Wākea''); is a dormant Shield volcano, shield volcano on the Hawaii (island), island of Hawaii. Its peak is above sea level, making it the List of U.S. states by elevation, highest point in Hawaii and List of islands by highest point, the island with the second highest high point, behind New Guinea, the world's largest tropical island with multiple peaks that are higher. The peak is about higher than Mauna Loa, its more massive neighbor. Mauna Kea is unusually Topographic prominence, topographically prominent for its height: its prominence from sea level is List of mountain peaks by prominence, 15th in the world among mountains, at ; its prominence from under the ocean is , rivaled only by Mount Everest. This Topographic prominence#Wet prominence and dry prominence, dry prominence is greater than Everest's height above sea level of , and some authorities have labeled Mauna Kea the tallest mountain in the world, from its underwater ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Flora Of Hawaii
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or becomin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
Ungulates
Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined to be a polyphyletic and thereby invalid clade based on molecular data. As a result, true ungulates had since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria while Paenungulata has been reclassified to a distant clade Afrotheria. Living ungulates are divided into two orders: Perissodactyla including equines, rhinoceroses, and tapirs; and Artiodactyla including cattle, antelope, pigs, giraffes, camels, sheep, deer, and hippopotamuses, among others. Cetaceans such as whales, dolphins, and porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. Two other orders o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Park Service
The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List of national parks of the United States, national parks; most National monument (United States), national monuments; and other natural, historical, and recreational properties, with various title designations. The United States Congress created the agency on August 25, 1916, through the National Park Service Organic Act. Its headquarters is in Washington, D.C., within the main headquarters of the Department of the Interior. The NPS employs about 20,000 people in units covering over in List of states and territories of the United States, all 50 states, the District of Columbia, and Territories of the United States, US territories. In 2019, the service had more than 279,000 volunteers. The agency is charged with preserving the ecological a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hylaeus (bee)
''Hylaeus'' is a large (over 500 species) and diverse cosmopolitan genus within the bee family Colletidae. This genus is also known as the yellow-faced bees or masked bees. This genus is the only truly globally distributed colletid, occurring on all continents except Antarctica. Description The genus of bees consists of generally small, black-and-yellow or black-and-white wasp-like species. The resemblance to wasps is enhanced by the absence of a scopa, which is atypical among bees. The body form of this genus is described as hylaeiform (slender); the hairs inconspicuous without magnification; and scopa inconspicuous or absent. Males have an intermediate glossal shape with a small to distinct median apical glossal point. ''Hylaeus'' carry pollen in the crop, rather than externally, and regurgitate it into the cell where it will be used as larval food. Like most colletids, the liquid provisions are sealed inside a membranous cellophane-like cell lining. Nests are typically made ... [...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] |
Sunflower
The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the production of cooking oil, as food for livestock, as bird food, and as plantings in domestic gardens for aesthetics. Wild plants are known for their multiple flower heads, whereas the domestic sunflower often possesses a single large flower head atop an unbranched stem. Description The plant has an erect rough-hairy stem, reaching typical heights of . The tallest sunflower on record achieved . Sunflower leaves are broad, coarsely toothed, rough and mostly alternate; those near the bottom are largest and commonly heart-shaped. Flower The plant flowers in summer. What is often called the " flower" of the sunflower is actually a "flower head" ( pseudanthium), wide, of numerous small individual five-petaled flowers (" florets"). The out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Senescence
Senescence () or biological aging is the gradual deterioration of Function (biology), functional characteristics in living organisms. Whole organism senescence involves an increase in mortality rate, death rates or a decrease in fecundity with increasing age, at least in the later part of an organism's biological life cycle, life cycle. However, the resulting effects of senescence can be delayed. The 1934 discovery that calorie restriction can Life extension, extend lifespans by 50% in rats, the existence of species having negligible senescence, and the existence of potentially immortal organisms such as members of the genus ''Hydra (genus), Hydra'' have motivated research into Life extension, delaying senescence and thus age-related diseases. Rare human mutations can cause accelerated aging diseases. Environmental Gerontogens, factors may affect aging – for example, overexposure to ultraviolet radiation accelerates skin aging. Different parts of the body may age at different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
