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Platyzamia
''Dioon'' is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes. Description Dioons are dioecious, palmlike shrubs with cylindrical stems, usually with many leaves. The species in the genus Dioon are perennial, evergreen cycads with cylindrical stem axis is partially in the ground. The plant is thickened and made of soft wood, rarely having above ground branches. Leaf bases are persistent or shedding to leave smooth bark. The leaves are pinnate, spirally arranged, interspersed with cataphylls, with leaflets not articulated and lacking a midrib. The lower leaflets are often reduced to spines. The sporophylls are not in vertical rows in cones, and the megasporophyll apices are broadly flattened, upturned, and overlapping. Species in the genus Dioon have 2n = 18 chromosomes. The largest species is D. spinolosum, which are over 16 meters high an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioon Edule
''Dioon edule'', the chestnut dioon, is a cycad native to Mexico, also known as ''palma de la virgen''. Cycads are among the oldest seed plants and even pre-date the dinosaurs.The United States Botanical Garden It belongs to the Zamiaceae plant family within the order Cycadales. The genus name "Dioon" means "two-egged", referring to the two ovules (see photo below). Two subspecies are known, the nominate subspecies growing in a moister environment than the other: *''Dioon edule'' subsp. ''angustifolium'' *''Dioon edule'' subsp. ''edule'' Anatomy ''Dioon edule'' is easily distinguished from other ''Dioon'' species because it lacks spines on the borders of leaflets. Spines are present on juvenile leaves but are lost when the plant matures. ''D. edule'' has a crown of pinnate (i.e. feathered) leaves which measure around 135 cm long. Lateral budding is present and mucilage, or sap, is excreted from any cut surfaces on the plant body. The plant has a large central medulla and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platyzamia
''Dioon'' is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes. Description Dioons are dioecious, palmlike shrubs with cylindrical stems, usually with many leaves. The species in the genus Dioon are perennial, evergreen cycads with cylindrical stem axis is partially in the ground. The plant is thickened and made of soft wood, rarely having above ground branches. Leaf bases are persistent or shedding to leave smooth bark. The leaves are pinnate, spirally arranged, interspersed with cataphylls, with leaflets not articulated and lacking a midrib. The lower leaflets are often reduced to spines. The sporophylls are not in vertical rows in cones, and the megasporophyll apices are broadly flattened, upturned, and overlapping. Species in the genus Dioon have 2n = 18 chromosomes. The largest species is D. spinolosum, which are over 16 meters high an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioon Spinolosum04
''Dioon'' is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes. Description Dioons are dioecious, palmlike shrubs with cylindrical stems, usually with many leaves. The species in the genus Dioon are perennial, evergreen cycads with cylindrical stem axis is partially in the ground. The plant is thickened and made of soft wood, rarely having above ground branches. Leaf bases are persistent or shedding to leave smooth bark. The leaves are pinnate, spirally arranged, interspersed with cataphylls, with leaflets not articulated and lacking a midrib. The lower leaflets are often reduced to spines. The sporophylls are not in vertical rows in cones, and the megasporophyll apices are broadly flattened, upturned, and overlapping. Species in the genus Dioon have 2n = 18 chromosomes. The largest species is D. spinolosum, which are over 16 meters high an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cataphyll
In plant morphology, a cataphyll (sometimes also called a ''cataphyllum'' or cataphyll leafJackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928) is a reduced, small leaf. Many plants have both "true leaves" (''euphylls''), which perform most of the photosynthesis, and cataphylls, which are modified to perform other functions. Cataphylls include bracts, bracteoles and bud scales, as well as any small leaves that resemble scales, known as scale leaves. The functions of cataphylls, such as bud scales, may be short-lived, and they are often shed after their function is fulfilled. Etymology Cataphyll comes from the Ancient Greek , meaning "down", and , meaning "leaf". Forms In some cases, cataphylls perform a transient function, after which they die and may shed. Those that shed early are said to be caducous. The sepals of '' Papaver'' species are shed during the very opening of the peta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zamia
''Zamia'' is a genus of cycad of the family Zamiaceae, native to North America from the United States (in Georgia and Florida) throughout the West Indies, Central America, and South America as far south as Bolivia. The genus is considered to be the most ecologically and morphologically diverse cycads, and is estimated to have originated about 68.3 million years ago. Description The genus comprises deciduous shrubs with aerial or subterranean circular stems, often superficially resembling palms. They produce spirally arranged, pinnate leaves which are pubescent, at least when young, having branched and simple, transparent and coloured hairs. The articulated leaflets lack a midrib, and are broad with subparallel dichotomous venation. Lower leaflets are not reduced to spines, though the petioles often have prickles. The emerging leaves of many ''Zamia'' species are striking, some emerging with a reddish or bronze cast ('' Z. roeslii'' being an example). ''Zamia picta'' is even mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact and possibly volcanism, marked the beginning of the Paleocene and killed off 75% of living species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. In the Paleocene, the continents of the Northern Hemisphere were still connected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenozoic
The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configuration of continents. It is the latest of three geological eras since complex life evolved, preceded by the Mesozoic and Paleozoic. It started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor. The Cenozoic is also known as the Age of Mammals because the terrestrial animals that dominated both hemispheres were mammalsthe eutherians (placentals) in the northern hemisphere and the metatherians (marsupials, now mainly restricted to Australia) in the southern hemisphere. The extinction of many groups allowed mammals and birds to greatly diversify so tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orography
Orography is the study of the topographic relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain. Orography (also known as ''oreography'', ''orology'' or ''oreology'') falls within the broader discipline of geomorphology. The term orography comes from the Greek: , hill, , to write. Uses Mountain ranges and elevated land masses have a major impact on global climate. For instance, the elevated areas of East Africa substantially determine the strength of the Indian monsoon.Srinivasan, J., Nanjundiah, Ravi S. and Chakraborty, Arindam (2005Impact of Orography on the Simulation of Monsoon Climate in a General Circulation Model''Indian Institute of Science'' In scientific models, such as general circulation models, orography defines the lower boundary of the model over land. When a river's tributaries or settlements by the river are listed in 'orographic sequence', they are in order from the highest (nearest the source of the river) to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honduras
Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, and to the north by the Gulf of Honduras, a large inlet of the Caribbean Sea. Its capital and largest city is Tegucigalpa. Honduras was home to several important Mesoamerican cultures, most notably the Maya, before the Spanish Colonization in the sixteenth century. The Spanish introduced Catholicism and the now predominant Spanish language, along with numerous customs that have blended with the indigenous culture. Honduras became independent in 1821 and has since been a republic, although it has consistently endured much social strife and political instability, and remains one of the poorest countries in the Western Hemisphere. In 1960, the northern part of what was the Mosquito Coast was transferred from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycas
''Cycas'' is a genus of plants belonging to a very ancient lineage, the Cycadophyta, which are not closely related to palms, ferns, trees or any other modern group of plants. They are evergreen perennials which achieved their maximum diversity in the Jurassic and Cretaceous periods, when they were distributed almost worldwide. At the end of the Cretaceous, when the non-avian dinosaurs became extinct, so did most of the cycas in the Northern Hemisphere. ''Cycas'' is the type genus and the only extant genus recognised in the family Cycadaceae. About 113 species are accepted. ''Cycas circinalis'', a species endemic to India, was the first cycad species to be described in western literature, and was the type of the generic name, ''Cycas''. The best-known ''Cycas'' species is '' Cycas revoluta''. Range The genus is native to the Old World, with the species concentrated around the equatorial regions - eastern and southeastern Asia including the Philippines with 10 species (9 of which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichomes
Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant is an indumentum, and the surface bearing them is said to be pubescent. Algal trichomes Certain, usually filamentous, algae have the terminal cell produced into an elongate hair-like structure called a trichome. The same term is applied to such structures in some cyanobacteria, such as '' Spirulina'' and '' Oscillatoria''. The trichomes of cyanobacteria may be unsheathed, as in ''Oscillatoria'', or sheathed, as in '' Calothrix''. These structures play an important role in preventing soil erosion, particularly in cold desert climates. The filamentous sheaths form a persistent sticky network that helps maintain soil structure. Plant trichomes Plant trichomes have many different features that vary between both species of plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stangeria Eriopus
''Stangeria eriopus'' is a cycad endemic to southern Africa. It is the sole species in the genus ''Stangeria'', most closely related to the Australian genus ''Bowenia'', with which it forms the family Stangeriaceae. Description ''Stangeria eriopus'' is a very long-lived, perennial, evergreen cycad. The stalked, feathered, fern-like leaves are between 25 centimeters and two meters long, with the petiole comprising one third to one half of the overall length (in both varieties). They are pinnately-veined, which distinguishes the species from all other cycads. The petiole comprises half the length of the leaf. The young leaves are bent in bud position, the tip appears rolled up. Young leaves are dotted with short, gray hairs (trichomes), which usually fall off quickly and only stick to the petiole. These trichomes are unbranched and transparent or colored. The species occurs as two variable forms or varieties. The forest form, growing in regions with higher rainfall, is characterize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
