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Osmundastrum Pulchellum
''Osmundastrum pulchellum'' is an extinct species of ''Osmundastrum'', leptosporangiate ferns in the family Osmundaceae from the lower Jurassic (Pliensbachian-Toarcian?) Djupadal Formation of Southern Sweden. It remained unstudied for 40 years. It is one of the most exceptional fossil ferns ever found, preserving intact calcified (thus dead) tissue with DNA and cells. Its exceptional preservation has allowed the study of the DNA relationships with extant Osmundaceae ferns, proving a 180-million-year genomic stasis. It has also preserved its biotic interactions and even ongoing mitosis. History and discovery The only known specimen was recovered at the mafic pyroclastic and epiclastic deposits of the Djupadal Formation, dated Pliensbachian-Toarcian(?), that are present near Korsaröd Lake, at the north of Höör, central Skåne, southern Sweden. The location was studied first by Gustav Andersson, a local farmer, who was a passionate follower of scientific discoveries. Through h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliensbachian
The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 190.8 ± 1.5 Ma and 182.7 ± 1.5 Ma (million years ago). The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian. The Pliensbachian ended with the extinction event called the Toarcian turnover. During the Pliensbachian, the middle part of the Lias was deposited in Europe. The Pliensbachian is roughly coeval with the Charmouthian regional stage of North America. Stratigraphic definitions The Pliensbachian takes its name from the hamlet of Pliensbach in the community of Zell unter Aichelberg in the Swabian Alb, some 30 km east of Stuttgart in Germany. The name was introduced into scientific literature by German palaeontologist Albert Oppel in 1858. The base of the Pliensbachian is at the first appearances of the ammonite species '' Bifericeras donovani'' and gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petiole (botany)
In botany, the petiole () is the stalk that attaches the leaf blade to the stem, and is able to twist the leaf to face the sun. This gives a characteristic foliage arrangement to the plant. Outgrowths appearing on each side of the petiole in some species are called stipules. Leaves with a petiole are said to be petiolate, while leaves lacking a petiole are called sessile or apetiolate. Description The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves, the leaf stalk may be long, as in the leaves of celery and rhubarb, or short. When completely absent, the blade attaches directly to the stem and is said to be sessile. Subpetiolate leaves have an extremely short petiole, and may appear sessile. The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile. In some other plant groups, such as the speedwell genus '' Veronica'', petiolate and sessile leaves may occur in different species. In the grasses ( Poacea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oribatida
Oribatida (formerly Cryptostigmata), also known as oribatid mites, moss mites or beetle mites, are an order of mites, in the "chewing Acariformes" clade Sarcoptiformes. They range in size from . There are currently 12,000 species that have been identified, but researchers estimate that there may be anywhere from 60,000 to 120,000 total species. Oribatid mites are by far the most prevalent of all arthropods in forest soils, and are essential for breaking down organic detritus and distributing fungi. Oribatid mites generally have low metabolic rates, slow development and low fecundity. Species are iteroparous with adults living a relatively long time; for example, estimates of development time from egg to adult vary from several months to two years in temperate forest soils. Oribatid mites have six active instars: prelarva, larva, three nymphal instars and the adult. All these stages after the prelarva feed on a wide variety of material including living and dead plant and fungal m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peronosporomycetes
Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result of contact between hyphae of male antheridia and female oogonia; these spores can overwinter and are known as resting spores. Asexual reproduction involves the formation of chlamydospores and sporangia, producing motile zoospores. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. One oomycete, the mycoparasite ''Pythium oligandrum'', is used for biocontrol, attacking plant pathogenic fungi. The oomycetes are also often referred to as water molds (or water moulds), although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens. Oom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kursk Region
Kursk Oblast ( rus, Курская область, r=Kurskaya oblast, p=ˈkurskəjə ˈobləsʲtʲ) is a federal subject of Russia (an oblast). Its administrative center is the city of Kursk. As of the 2010 Census, Kursk Oblast has a population of 1,127,081. Geography The oblast, with an average elevation of , occupies the southern slopes of the middle-Russian plateau. The surface is hilly and intersected by ravines. The central part of Kursk oblast is more elevated than the Seym Valley to the west. The Timsko-Shchigrinsky ridge contains the highest point in the oblast at above the sea level. The low relief, gentle slopes, and mild winters make the area suitable for farming, and much of the forest has been cleared. Chernozem soils cover around 70% of the oblast's territory; podsol soils cover 26%. ;Borders: ''Internal'': Bryansk Oblast (NW) (border length: ), Oryol Oblast (N, ), Lipetsk Oblast (NE, ), Voronezh Oblast (E, ), Belgorod Oblast (S, ). ''International'': Sumy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmundastrum Gvozdevae
''Osmundastrum'' is genus of leptosporangiate ferns in the family Osmundaceae with one living species, ''Osmundastrum cinnamomeum'', the cinnamon fern. It is native to the Americas and eastern Asia, growing in swamps, bogs and moist woodlands. In North America it occurs from southern Labrador west to Ontario, and south through the eastern United States to eastern Mexico and the West Indies; in South America it occurs west to Peru and south to Paraguay. In Asia it occurs from southeastern Siberia south through Japan, Korea, China and Taiwan to Myanmar, Thailand and Vietnam. ''Osmundastrum cinnamomeum'' has a fossil record extending into the Late Cretaceous of North America, approximately 70 million years ago, making it one of the oldest living plant species. The fossil records of the genus extend into the Triassic. Characteristics ''Osmundastrum cinnamomeum'' is a deciduous herbaceous plant that produces separate fertile and sterile fronds. The sterile fronds are spreading, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claytosmunda
''Claytosmunda'' is a genus of fern. It has only one extant species, ''Claytosmunda claytoniana'' (synonym ''Osmunda claytoniana''), the interrupted fern, native to Eastern Asia, Eastern United States, and Eastern Canada. The specific epithet is named after the English-born Virginian botanist John Clayton. "Interrupted" describes the gap in middle of the blade left by the fertile portions after they wither and eventually fall off. The plant is known from fossils to have grown in Europe, showing a previous circumboreal distribution. Fragmentary foliage resembling ''Claytosmunda'' has been found in the fossil record as far back as the Triassic. Description ''Claytosmunda claytoniana'' fronds are bipinnate, tall and broad, the blade formed of alternate segments forming an arching blade tightening to a pointed end. The lower end is also slightly thinner than the rest of the frond because the first segments are shorter. Three to seven short, cinnamon-colored fertile segments are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plenasium
''Plenasium'' is a genus of ferns in the family Osmundaceae. It is recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), but kept within a more broadly circumscribed genus ''Osmunda ''Osmunda'' is a genus of primarily temperate-zone ferns of family Osmundaceae. Five to ten species have been listed for this genus. Description Completely dimorphic fronds or pinnae (hemidimorphic), green photosynthetic sterile fronds, and n ...'' by other sources. The genus is known from Early Cretaceous to present. Taxonomy , the ''Checklist of Ferns and Lycophytes of the World'' accepted the following four species: Phylogeny of ''Plenasium'' The following fossil species are also accepted. * †''P. arnoldii'' (C.N.Mill. 1967) Bomfleur, Grimm & McLoughlin 2017 * †''P. bransonii'' (Tidwell & Medlyn, 1991) Bomfleur, Grimm & McLoughlin 2017 (?Eocene: New Mexico, USA). * †''P. burgii'' (Tidwell & J.E.Skog, 2002) Bomfleur, Grimm & McLoughlin 2017 (Early Creta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptopteris
The fern genus ''Leptopteris'' is a small group of plants found growing in the Pacific Islands, New Guinea and Australia. They are similar to ferns in the related genus '' Todea'', and were originally included in that genus. However, the very thin fronds of ''Leptopteris'' differ from the thick leathery fronds of '' Todea'', and the genera are considered distinct. A probable extinct species, ''Leptopteris estipularis'' is known from the Early Cretaceous of India. Species Species include: * '' L. alpina'' (Baker) C. Chr. * †'' L. estipularis'' (Sharma, Bohra & Singh) Bomfleur, Grimm & McLoughlin * '' L. fraseri'' (Hooker & Grev.) Presl (Crepe fern, Australia) * '' L. hymenophylloides'' (Richard) Presl (Single crepe fern) * '' L. x intermedia'' (André) Brownsey * ''L. laxa ''Freesia laxa'', commonly known as flowering grass, is a small species of cormous flowering plant in the family Iridaceae, from eastern and southern Africa, from Kenya to northeastern South Africa. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Todea
The fern genus ''Todea'' is known from only two living species. '' Todea barbara'' L., known as the king fern, is native to South Africa, New Zealand, and Australia while '' Todea papuana'' H. is known only from Papua New Guinea. Species in the genus ''Todea'', as ''Leptopteris'', are distinct from other in Osmundaceae in that sporangia are born on laminar pinnules. So far the fossil record of the genus ''Todea'' consists only of the permineralized rhizome '' Todea tidwellii'' from the Lower Cretaceous of Vancouver Island, Canada and the species ''Todea amissa'', known from the Eocene of Patagonia, Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t .... References Bibliography * Nathan Jud, Gar W.Rothwell and Ruth A. Stockey. 2008. "''Todea'' from the Lower Cretaceous of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amyloplast
Amyloplasts are a type of plastid, double-enveloped organelles in plant cells that are involved in various biological pathways. Amyloplasts are specifically a type of leucoplast, a subcategory for colorless, non-pigment-containing plastids. Amyloplasts are found in roots and storage tissues, and they store and synthesize starch for the plant through the polymerization of glucose. Starch synthesis relies on the transportation of carbon from the cytosol, the mechanism by which is currently under debate. Starch synthesis and storage also takes place in chloroplasts, a type of pigmented plastid involved in photosynthesis. Amyloplasts and chloroplasts are closely related, and amyloplasts can turn into chloroplasts; this is for instance observed when potato tubers are exposed to light and turn green. Role in gravity sensing Amyloplasts are thought to play a vital role in gravitropism. Statoliths, a specialized starch-accumulating amyloplast, are denser than cytoplasm, and are able to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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