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Physematium Obtusum
''Physematium obtusum'', the bluntlobe cliff fern, is a common rock fern of Appalachia and eastern North America. It prefers a calcareous substrate, but also grows in neutral soils. It may grow on rock faces or in scree. This fern is often confused with various ferns of the genus ''Cystopteris ''Cystopteris'' is a genus of ferns in the family Cystopteridaceae. These are known generally as bladderferns or fragile ferns. They grow in temperate areas worldwide. This is a very diverse genus and within a species individuals can look quite ...'' but is distinguished by its hairy nature. References obtusum Ferns of Canada Ferns of the United States Plants described in 1840 {{Polypodiales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torr
The torr (symbol: Torr) is a Pressure#Units, unit of pressure based on an absolute scale, defined as exactly of a standard atmosphere (unit), atmosphere (101325 Pa). Thus one torr is exactly (≈ ). Historically, one torr was intended to be the same as one "millimetre of mercury", but subsequent redefinitions of the two units of measurement, units made the torr marginally lower (by less than 0.000015%). The torr is not part of the International System of Units (SI). Even so, it is often combined with the metric prefix milli to name one millitorr (mTorr), equal to 0.001 Torr. The unit was named after Evangelista Torricelli, an Italian physicist and mathematician who discovered the principle of the barometer in 1644. Nomenclature and common errors The unit name ''torr'' is written in letter case, lower case, while its symbol ("Torr") is always written with an uppercase initial; including in combinations with prefixes and other unit symbols, as in "mTorr" (millitorr) or " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appalachia
Appalachia ( ) is a geographic region located in the Appalachian Mountains#Regions, central and southern sections of the Appalachian Mountains in the east of North America. In the north, its boundaries stretch from the western Catskill Mountains of New York, continuing south through the Blue Ridge Mountains and Great Smoky Mountains into northern Georgia (US state), Georgia, Alabama, and Mississippi, with West Virginia near the center, being the only state entirely within the boundaries of Appalachia. In 2021, the region was home to an estimated 26.3 million people. Since its recognition as a cultural region in the late 19th century, Appalachia has been a source of Appalachian stereotypes, enduring myths and distortions regarding the isolation, temperament, and behavior of its inhabitants. Early 20th-century writers often engaged in yellow journalism focused on Sensationalism, sensationalistic aspects of the region's culture, such as moonshining and #Feuds, clan feuding, p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the south and west by the Pacific Ocean. The region includes Middle America (Americas), Middle America (comprising the Caribbean, Central America, and Mexico) and Northern America. North America covers an area of about , representing approximately 16.5% of Earth's land area and 4.8% of its total surface area. It is the third-largest continent by size after Asia and Africa, and the list of continents and continental subregions by population, fourth-largest continent by population after Asia, Africa, and Europe. , North America's population was estimated as over 592 million people in list of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cystopteris
''Cystopteris'' is a genus of ferns in the family Cystopteridaceae. These are known generally as bladderferns or fragile ferns. They grow in temperate areas worldwide. This is a very diverse genus and within a species individuals can look quite different, especially in harsh environments where stress stunts their growth. They hybridize easily with each other and identifying an individual can be challenging. In general these are rhizomatous perennials which grow in rocks or soil. Their leaves are multiply pinnate, in that each leaflet is divided into smaller parts. The sori are usually rounded and covered in an inflated bladder-like indusium. Phylogeny This genus includes the following species: Hybrids The hybrid species include: *'' C. fragilis'' (''C. "hemifragilis"'' × ''C. reevesiana''; allotetraploid) *'' C. laurentiana'' (''C. bulbifera'' × ''C. fragilis''; allohexaploid) *'' C. tennesseensis'' (''C. bulbifera'' × ''C. protrusa''; allotetraploid) *'' C. tenuis'' ('' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physematium
''Physematium'' is a genus of ferns in the family Woodsiaceae. It was treated as a synonym of ''Woodsia'' until 2020 when a molecular phylogenetic study showed its distinctiveness. , Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ... continued to treat the genus as a synonym of ''Woodsia''. Phylogeny , World Ferns accepted 20 species and two hybrids: References Fern genera {{Polypodiales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferns Of Canada
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaves called megaphylls that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate ( Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. The fern crown group, consisting of the leptosporangiates and eusporangiates, is estimated to have originated in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
