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Drepanophycus
''Drepanophycus'' is a genus of extinct plants of the division Lycopodiophyta of Early to Late Devonian age (around ), found in Eastern Canada and Northeast US, China, Russia, Egypt and various parts of Northern Europe and Britain. Description Extinct terrestrial vascular plants of the Devonian period. Stem of the order of several mm to several cm in diameter and several cm to a metre long, erect or arched, dichotomizing occasionally, furnished with true roots at the base. Vascular bundle actinostele, tracheids of primitive annular or helical type (so-called G-type). Leaves are unbranched thorn-shaped (i.e. with a wide base, tapering to a blunt point) microphylls several mm long with a single prominent vascular thread, arranged spirally to randomly on the stem. Sporangia borne singly on the upper leaf surface. ''Drepanophycus'' has similarities to the genus ''Halleophyton''. It differs from a closely related genus of the same period, Baragwanathia, in the position of the sporang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drepanophycaceae
Drepanophycaceae is a family of extinct lycophytes of Late Silurian to Late Devonian age (), found in North America, China, Russia, Europe, and Australia. Description The stems are several mm to several cm in diameter and several cm to several metres long, erect or arched, dichotomizing occasionally, furnished with true roots at the base.Hueber 1992, p. 491 (''Baragwanathia'') and 492 (''Drepanophycus'') Vascular bundle an exarch actinostele, tracheids of primitive annular or helical type (so-called G-type). Leaves are unbranched microphylls several mm to 2 cm or more long with a single prominent vascular thread, arranged spirally to randomly on the stem. Homosporous sporangia borne singly on the upper leaf surface or in an axillary position.See tables 2 & 3 in Gensel (1992) for list of these anatomical details. Drepanophycaceae differs from a related family of the same period, Asteroxylaceae, in having vascularized microphylls; see Drepanophycales for more details. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroxylon
''Asteroxylon'' ("star-shaped xylem") is an extinct genus of vascular plants of the Division Lycopodiophyta known from anatomically preserved specimens described from the famous Early Devonian Rhynie chert and Windyfield chert in Aberdeenshire, Scotland. ''Asteroxylon'' is considered a basal member of the Lycopsida. Description ''Asteroxylon'' is a genus of terrestrial vascular plant which flourished in the Early Devonian period. This plant consisted of aerial, isotomously and anisotomously branching stems that reached 12 mm in diameter and 40 cm in length. The possibly procumbent aerial stems arose from a leaf-less rhizome which bore smaller-diameter, positively geotropic root-like branches. The rhizomes, which represent an independent origin of roots, reached a depth of up to 20 cm below the surface. A 407 million-year-old fossil from the Rhynie chert shows the roots formed through a modified version of a mechanism called “dichotomous branching”, where one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drepanophycales
Drepanophycales is an order of extinct lycopsid plants of Late Silurian to Late Devonian age (around ), found in North America, China, Russia, Europe, and Australia. Sometimes known as the Asteroxylales or Baragwanathiales. Description Extinct terrestrial vascular plants of the Silurian to Devonian periods. Stem of the order of several mm to several cm in diameter and several cm to several metres long, erect or arched, dichotomizing occasionally, furnished with true roots at the base. Vascular bundle an exarch actinostele, tracheids of primitive annular or helical type (so-called G-type). Stem clothed in either microphylls (leaves with a single vascular thread or 'vein'), or with leaf-like enations (unvascularized projections) with a vascular trace into the base of each enation. Homosporous, with sporangia borne singly and dehiscing by a single slit. List of families The following families have, at various times, been segregated within the Drepanophycales. However, Kenrick and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baragwanathia
''Baragwanathia'' is a genus of extinct lycopsid plants of Late Silurian to Early Devonian age (), fossils of which have been found in Australia, Canada, China and Czechia. The name derives from William Baragwanath who discovered the first specimens of the type species, ''Baragwanathia longifolia'', at Thomson River (Victoria, Australia). Description ''Baragwanathia'' differed from such taxa as ''Asteroxylon'' by the presence of vascular tissue in its leaves—''Asteroxylon'' had enations without vascular tissue. The sporangia were borne in the axils of the leaves, which were spirally arranged. By comparison, the closely related genus ''Drepanophycus'' of the same period (see Drepanophycaceae for more details) bore its sporangia on the upper surface of specialized leaves known as sporophylls. ''Baragwanathia'' varied in size, with stems up to a few cm in diameter and up to a few metres in length. They were erect or arched, dichotomized (forked) occasionally, and had adventit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halleophyton
''Halleophyton'' is a genus of extinct vascular plants of the Early Devonian (Pragian, around ). Fossils were first found in the Posongchong Formation of eastern Yunnan, China. The plant had leafy aerial stems. The leaf bases completely covered the stems forming rhomboidal to hexagonal patterns, except where spore-forming organs or sporangia were present where the leaves thinned out somewhat. The tapered undivided leaves curved inwards and appear to have had a central vein. The sporangia were mixed with leaves and were more-or-less circular in outline, consisting of two valves which split to release the spores. ''Halleophyton'' has similarities with ''Drepanophycus'', but a lack of detailed knowledge of some features of that genus persuaded Li and Edwards to create a new genus for their specimens. Although considered to be related to the lycophytes, the exact placement of the genus was left open by its authors. Hao and Xue in 2013 listed the genus as a lycopsid Lycopodiopsid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediterranean Sea to the north, the Gaza Strip of Palestine and Israel to the northeast, the Red Sea to the east, Sudan to the south, and Libya to the west. The Gulf of Aqaba in the northeast separates Egypt from Jordan and Saudi Arabia. Cairo is the capital and largest city of Egypt, while Alexandria, the second-largest city, is an important industrial and tourist hub at the Mediterranean coast. At approximately 100 million inhabitants, Egypt is the 14th-most populated country in the world. Egypt has one of the longest histories of any country, tracing its heritage along the Nile Delta back to the 6th–4th millennia BCE. Considered a cradle of civilisation, Ancient Egypt saw some of the earliest developments of writing, agriculture, ur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People's Republic Of China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and borders fourteen countries by land, the most of any country in the world, tied with Russia. Covering an area of approximately , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai. Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomata
In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the stomatal opening. The term is usually used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself, which is referred to as the stomatal aperture. Air, containing oxygen, which is used in respiration, and carbon dioxide, which is used in photosynthesis, passes through stomata by gaseous diffusion. Water vapour diffuses through the stomata into the atmosphere in a process called transpiration. Stomata are present in the sporophyte generation of all land plant groups except liverworts. In vascular plants the number, size and distribution of stomata varies widely. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Khakassia
Khakassia (russian: Хакасия; kjh, Хакасия, Хакас Чирі, ''Khakasiya'', ''Khakas Çiri''), officially the Republic of Khakassia (russian: Республика Хакасия, r=Respublika Khakasiya, ; kjh, Хакас Республиказы, tr. ''Khakas Respublikazy''), is a federal subject (a republic) of Russia. Its capital city is Abakan, which is also the largest city in the republic. As of the 2010 Census, the republic's population was 532,403. Geography The republic is located in the southwestern part of Eastern Siberia and borders Krasnoyarsk Krai in the north and east, the Tuva Republic in the southeast and south, the Altai Republic in the south and southwest, and Kemerovo Oblast in the west and northwest. It stretches for from north to south and for from east to west. Mountains (eastern slopes of Kuznetsk Alatau and the Abakan Range) cover two-thirds of the republic's territory and serve as the natural boundaries of the republic. The hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopodium
''Lycopodium'' (from Greek ''lykos'', wolf and ''podion'', diminutive of ''pous'', foot) is a genus of clubmosses, also known as ground pines or creeping cedars, in the family Lycopodiaceae. Two very different circumscriptions of the genus are in use. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), ''Lycopodium'' is one of nine genera in the subfamily Lycopodioideae, and has from nine to 15 species. In other classifications, the genus is equivalent to the whole of the subfamily, since it includes all of the other genera. More than 40 species are accepted. Description They are flowerless, vascular, terrestrial or epiphytic plants, with widely branched, erect, prostrate, or creeping stems, with small, simple, needle-like or scale-like leaves that cover the stem and branches thickly. The leaves contain a single, unbranched vascular strand, and are microphylls by definition. The kidney-shaped (reniform) spore-cases (sporangia) contain spores of one kind only, ( i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
