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Vandenboschia Boschiana
''Vandenboschia boschiana'', synonym ''Trichomanes boschianum'', the Appalachian bristle fern or Appalachian filmy fern, is a small delicate perennial leptosporangiate fern which forms colonies with long, black creeping rhizomes. The evergreen fronds are bipinnatifid, deeply and irregularly dissected, about 4 to 20 cm long, 1 to 4 cm across with winged stipes 1 to 7 cm long and light green in colour. The common name derives from the leaves which are very thin, only a single cell thick, missing an epidermis and translucent, giving the appearance of a wet film. Sori, the spore-producing organs are formed along the margins of the frond segments. The indusium forms a funnel around the sorus which is sunken in the leaf tissue. A bristle-like receptacle protrudes from the indusium as in all ''Trichomanes'' species. Spore production occurs between July and September. In common with all ferns, ''V. boschiana'' exhibits a gametophyte stage in its life cycle (alternation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Wilhelm Sturm
Johann Wilhelm Sturm (1808-1865) was Germany, German botanist. Works * With Jacob Sturm - ''Deutschlands Flora in Abbildungen nach der Natur mit beschreibungen'' - Nuremberg, 1817 * Nymphaea semiaperta Klinggraff, eine fur Bayern neue pflanze, bei Nurnberg aufgefunden - Abhandlungen der Naturhistorischen Gesellschaft zu Nürnberg, Nuremberg, 1858 * Ophioglosseae, Marattiaceae, Osmundaceae, Schizaeaceae, Gleicheniaceae, Hymeanophylleae - in Flora brasiliensis, Leipzig, 1854 References {{DEFAULTSORT:Sturm, Johann Wilhelm 19th-century German botanists 1808 births 1865 deaths Scientists from Nuremberg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protonemata
A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage of development of the gametophyte (the haploid phase) in the life cycle of mosses. When a moss first grows from a spore, it starts as a ''germ tube'', which lengthens and branches into a filamentous complex known as a ''protonema'', which develops into a leafy gametophore, the adult form of a gametophyte in bryophytes. Moss spores germinate to form an alga-like filamentous structure called the protonema. It represents the juvenile gametophyte. While the protonema is growing by apical cell division, at some stage, under the influence of the phytohormone cytokinin, buds are induced which grow by three-faced apical cells. These give rise to gametophores, stems and leaf like structures. Bryophytes do not have true leaves (megaphylls). Protonemata are characteristic of all mosses and some liverworts but are absent from hornworts. Protonemata of mosses are composed of two cell types: chloron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flora Of The Southeastern United States
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms ''gut flora'' or '' skin flora''. Etymology The word "flora" comes from the Latin name of Flora, the goddess of plants, flowers, and fertility in Roman mythology. The technical term "flora" is then derived from a metonymy of this goddess at the end of the sixteenth century. It was first used in poetry to denote the natural vegetation of an area, but soon also assumed the meaning of a work cataloguing such vegetation. Moreover, "Flora" was used to refer to the flowers of an artificial garden in the seventeenth century. The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms were used indiscriminately.Thurmann, J. (1849). ''Essai de Phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flora Of The Northeastern United States
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. Etymology The word "flora" comes from the Latin name of Flora, the goddess of plants, flowers, and fertility in Roman mythology. The technical term "flora" is then derived from a metonymy of this goddess at the end of the sixteenth century. It was first used in poetry to denote the natural vegetation of an area, but soon also assumed the meaning of a work cataloguing such vegetation. Moreover, "Flora" was used to refer to the flowers of an artificial garden in the seventeenth century. The distinction between vegetation (the general appearance of a community) and flora (the taxonomic composition of a community) was first made by Jules Thurmann (1849). Prior to this, the two terms were used indiscriminately.Thurmann, J. (1849). ''Essai de P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hymenophyllales
The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera (depending on classification system) and about 650 known species of ferns, with a cosmopolitan distribution, subcosmopolitan distribution, but generally restricted to very damp places or to locations where they are wetted by spray from waterfalls or springs. A recent fossil find shows that ferns of Hymenophyllaceae have existed since at least the Upper Triassic. Description They often appear as very dark green or even black clumps and may be mistaken for a robust moss or Marchantiophyta, liverwort. The rhizome is usually thin and wiry and the fronds variously pinnate with a single strand ("nerve") of vascular tissue. As in most ferns, young fronds have circinate vernation. In most species, the frond, apart from the vascular tissue, is only a single cell thick, and they do not have any stomata. The plant cuticle, cuticle is also greatly reduced or absent, leaving filmy ferns very susceptible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USDA Hardiness Zone
A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most widely used system, developed by the United States Department of Agriculture (USDA) as a rough guide for landscaping and gardening, defines 13 zones by long-term average annual extreme minimum temperatures. It has been adapted by and to other countries (such as Canada) in various forms. Unless otherwise specified, in American contexts "hardiness zone" or simply "zone" usually refers to the USDA scale. For example, a plant may be described as "hardy to zone 10": this means that the plant can withstand a minimum temperature of 30 °F (−1.1 °C) to 40 °F (4.4 °C). Other hardiness rating schemes have been developed as well, such as the UK Royal Horticultural Society and US Sunset Western Garden Book systems. A heat zone (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NatureServe Conservation Status
The NatureServe conservation status system, maintained and presented by NatureServe in cooperation with the Natural Heritage Network, was developed in the United States in the 1980s by The Nature Conservancy (TNC) as a means for ranking or categorizing the relative imperilment of species of plants, animals, or other organisms, as well as natural ecological communities, on the global, national or subnational levels. These designations are also referred to as NatureServe ranks, NatureServe statuses, or Natural Heritage ranks. While the Nature Conservancy is no longer substantially involved in the maintenance of these ranks, the name TNC ranks is still sometimes encountered for them. NatureServe ranks indicate the imperilment of species or ecological communities as natural occurrences, ignoring individuals or populations in captivity or cultivation, and also ignoring non-native occurrences established through human intervention beyond the species' natural range, as for example w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NatureServe
NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and the public. NatureServe reports being "headquartered in Arlington, Virginia, with regional offices in four U.S. locations and in Canada." In calendar year 2011 they reported having 86 employees, 6 volunteers, and 15 independent officers. History The Nature Conservancy reports that in 2000 it spun off its 85-center Natural Heritage Network "into a new independent organization, the Association for Biodiversity Information (later renamed NatureServe)." NatureServe reports that it was established in 1994 as the Association for Biodiversity Information. In 2001 the IRS approved a name change to NatureServe that was requested in 1999, while maintaining the organization's 501(c)(3) tax-exempt status granted in July 1995. NatureServe's website declares that it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micro-climate
A microclimate (or micro-climate) is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few square meters or square feet (for example a garden bed or a cave) or as large as many square kilometers or square miles. Because climate is statistical, which implies spatial and temporal variation of the mean values of the describing parameters, within a region there can occur and persist over time sets of statistically distinct conditions, that is, microclimates. Microclimates can be found in most places but are most pronounced in topographically dynamic zones such as mountainous areas, islands, coastal areas. Microclimates exist, for example, near bodies of water which may cool the local atmosphere, or in heavy urban areas where brick, concrete, and asphalt absorb the sun's energy, heat up, and re-radiate that heat to the ambient air: the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relict (biology)
In biogeography and paleontology, a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population currently inhabiting a restricted area whose range was far wider during a previous geologic epoch. Similarly, a relictual taxon is a taxon (e.g. species or other lineage) which is the sole surviving representative of a formerly diverse group. Definition A relict (or relic) plant or animal is a taxon that persists as a remnant of what was once a diverse and widespread population. Relictualism occurs when a widespread habitat or range changes and a small area becomes cut off from the whole. A subset of the population is then confined to the available hospitable area, and survives there while the broader population either shrinks or evolves divergently. This phenomenon differs from endemism in that the range of the population was not always restricted to the local region. In other words, the species or group did n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Shelters
A rock shelter (also rockhouse, crepuscular cave, bluff shelter, or abri) is a shallow cave-like opening at the base of a bluff or cliff. In contrast to solutional caves ( karst), which are often many miles long, rock shelters are almost always modest in size and extent. Formation Rock shelters form because a rock stratum such as sandstone that is resistant to erosion and weathering has formed a cliff or bluff, but a softer stratum, more subject to erosion and weathering, lies just below the resistant stratum, and thus undercuts the cliff. In arid areas, wind erosion (Aeolian erosion) can be an important factor in rockhouse formation. In most humid areas, the most important factor in rockhouse formation is frost spalling, where the softer, more porous rock underneath is pushed off, tiny pieces at a time, by frost expansion from water frozen in the pores. Erosion from moving water is seldom a significant factor. Many rock shelters are found under waterfalls. File:Rock shel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triploid
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains one or more chromosomes and comes from each of two parents, resulting in pairs of homologous chromosomes between sets. However, some organisms are polyploid. Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations. The gametophyte generation is haploid, and produces gametes by mitosis, the sporophyte generation is diploid and produces spores by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
