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Marsilea Villosa
''Marsilea villosa'', the ihiihi (Hawaiian language, Hawaiian) or villous waterclover (English language, English), is a species of fern that is Endemism, endemic to the islands of Oahu, Oahu, Molokai, Molokai and Niihau, Niihau in Hawaii. It is found exclusively in areas that experience periodic flooding and become Vernal pool, ephemeral pools within low elevation Hawaiian tropical dry forests, dry forests and Hawaiian tropical low shrublands, shrublands. Standing water allows the Sporocarp (ferns), sporocarp to open and release spores. It also enables the resulting sperm to swim toward and Fertilization, fertilize female Ovum, ova. For new plants to become established, the waters must subside. Sporocarps only form once the soil has dried to a certain level. Like other species in its genus, the leaves of ''M. villosa'' resemble those of a four-leaf clover. Conservation Fewer than 2,000 individual plants exist in four remaining populations. The plant was federally listed as an Enda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg Friedrich Kaulfuss
Georg Friedrich Kaulfuss (8 April 1786 – 9 December 1830) was a professor at Halle. He described the pteridophytes collected by Adelbert von Chamisso, and he named the fern ''Cibotium chamissoi'' after him. The genus ''Kaulfussia'' is named for Kaulfuss. In 1816 he obtained his doctorate from the University of Halle, where in 1823 he became a full professor of botany. Plants Named by Kaulfuss More than 200 plant names were published by Kaulfuss. Tropicos.org. Missouri Botanical Garden. 01 Feb 2012 These include the genera: * *'''' * *'' Balantium'' * Plant families named by Kaulfuss in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian Tropical Low Shrublands
The Hawaiian tropical low shrublands are a tropical savanna ecoregion in the Hawaiian Islands. Geography These shrublands cover an area of in the leeward lowlands of the main islands and most of the smaller islands, not including the Northwestern Hawaiian Islands which form an ecoregion of their own. Flora The ecoregion includes both grasslands and mixed shrublands. Kāwelu (''Eragrostis variabilis''), mauu akiaki (''Fimbristylis cymosa''), akiaki (''Sporobolus virginicus''), and ''Lepturus repens'' are common grassland plants. Shrublands are dominated by ilima (''Sida fallax''), aalii (''Dodonaea viscosa''), naupaka ('' Scaevola'' spp.), hinahina kū kahakai ( ''Heliotropium anomalum'' var. ''argenteum''), kīpūkai ('' Heliotropium curassavicum''), mao (''Gossypium tomentosum''), akoko (''Euphorbia'' spp.), āheahea (''Chenopodium oahuense''), naio (''Myoporum sandwicense''), kolokolo kahakai (''Vitex rotundifolia''), and pūkiawe (''Styphelia tameiameiae''). More than 90 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsilea
''Marsilea'' is a genus of approximately 65 species of aquatic ferns of the family Marsileaceae. The name honours Italian naturalist Luigi Ferdinando Marsili (1656–1730). These small plants are of unusual appearance and do not resemble common ferns. Common names include water clover and four-leaf clover because of the long-stalked leaves have four clover-like lobes and are either present above water or submerged. The sporocarps of some Australian species are very drought-resistant, surviving up to 100 years in dry conditions. On wetting, the gelatinous interior of the sporocarp swells, splitting it and releasing a worm-like mass that carries sori, eventually leading to germination of spores and fertilization. Uses As food Sporocarps of some Australian species such as ''Marsilea drummondii'' are edible and have been eaten by Aborigines and early white settlers, who knew it under the name ngardu or nardoo. Parts of ''Marsilea drummondii'' contain an enzyme which destroys t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endangered Species Act
The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation", the ESA was signed into law by President Richard Nixon on December 28, 1973. The Supreme Court of the United States described it as "the most comprehensive legislation for the preservation of endangered species enacted by any nation"."Tennessee Valley Authority v. Hill" 437 U.S. 153 (1978) Retrieved 24 November 2015. The purposes of the ESA are two-fold: to prevent extinction and to recover species to the point where the law's protections are not needed. It therefo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a census, a process of collecting, analysing, compiling, and publishing data regarding a population. Perspectives of various disciplines Social sciences In sociology and population geography, population refers to a group of human beings with some predefined criterion in common, such as location, race, ethnicity, nationality, or religion. Demography is a social science which entails the statistical study of populations. Ecology In ecology, a population is a group of organisms of the same species who inhabit the same particular geographical area and are capable of interbreeding. The area of a sexual population is the area where inter-breeding is possible between any pair within the area and more probable than cross-breeding with in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Four-leaf Clover
The four-leaf clover is a rare variation of the common three-leaf clover. According to traditional sayings, such clovers bring good luck, though it is not clear when or how this idea began. One early mention of "Fower-leafed or purple grasse" is from 1640 and simply says that it was kept in gardens because it was "good for the purples in children or others". Occurrence An actual survey of approximately 7 million clovers found the frequency to be about 5000 to 1, twice the commonly stated probability of 10,000 to 1. According to this survey, the frequency of a five-leaf clover is 24,400 to 1, and of a six-leaf clover is 312,500 to 1. " share the luck; Bern, Switzerland, 2017: "How rare are four-leaf clovers really?" Even so, this probability has not deterred collectors who have reached records as high as 160,000 four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovum
The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capable of movement (non-motile). If the male gamete (sperm) is capable of movement, the type of sexual reproduction is also classified as oogamous. A nonmotile female gamete formed in the oogonium of some algae, fungi, oomycetes, or bryophytes is an oosphere. When fertilized the oosphere becomes the oospore. When egg and sperm fuse during fertilisation, a diploid cell (the zygote) is formed, which rapidly grows into a new organism. History While the non-mammalian animal egg was obvious, the doctrine ''ex ovo omne vivum'' ("every living nimal comes froman egg"), associated with William Harvey (1578–1657), was a rejection of spontaneous generation and preformationism as well as a bold assumption that mammals also reproduced via ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally called fertilisation. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In Antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote in frog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sperm
Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, which are known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia. Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. Sperm cells form during the process known as spermatogenesis, which in amniotes ( reptiles and mammals) takes place in the seminiferous tubules of the testes. This process involves the production of several successive sperm cell precursors, starting with spermatogonia, which differentiate into spermatocytes. The spermatocytes then undergo meiosis, reducing their chromosome number by half, which produces spermatids. The spermatids then mature and, in animals, construct a tail, or flagellum, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoeboid infectious germs ("amoebulae") into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. In plants, spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporocarp (ferns)
A sporocarp is a specialised type of structure in the aquatic ferns of the order Salviniales whose primary function is the production and release of spores. Sporocarps are found only in the Salviniales, a group that is aquatic and heterosporous, but the structures are very different in the two families of the order. In the Salviniaceae family, the sporocarp is nothing more than a modified sorus, a single cluster of spore-producing tissues enclosed by a thin sphere of tissue and attached to the leaves. In the Marsileaceae (water-clover) family, the sporocarp is a more elaborate structure formed from an entire leaf whose development and form is greatly modified. These are hairy, short-stalked, bean-shaped structures (usually 3 to 8 mm in diameter) with a hardened outer covering. This outer covering is tough and resistant to drying out, allowing the spores inside to survive unfavorable conditions such as winter frost or summer desiccation. Despite this toughness, the sporocarps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian Tropical Dry Forests
The Hawaiian tropical dry forests are a tropical dry broadleaf forest ecoregion in the Hawaiian Islands. They cover an area of on the leeward side of the main islands and the summits of Niihau and Kahoolawe. These forests are either seasonal or sclerophyllous. Annual rainfall is less than and may be as low as ; the rainy season lasts from November to March. Dominant tree species include koa (''Acacia koa''), koaia ('' A. koaia''), akoko (''Euphorbia'' spp.), ōhia lehua (''Metrosideros polymorpha''), lonomea ('' Sapindus oahuensis''), māmane (''Sophora chrysophylla''), loulu ('' Pritchardia'' spp.), lama (''Diospyros sandwicensis''), olopua ('' Nestegis sandwicensis''), wiliwili (''Erythrina sandwicensis''), and iliahi (''Santalum'' spp.). Endemic plant species in the dry forests include hau heleula (''Kokia cookei''), uhiuhi (''Caesalpinia kavaiensis''), and '' Gouania'' spp. The palila (''Loxioides bailleui''), a Hawaiian honeycreeper, is restricted to this type of hab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
