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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] |
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) became fully terrestrialized. A significant evolutionary milestone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopodiopsida
Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms formed huge forests that dominated the landscape and contributed to coal deposits. The nomenclature and classification of plants with microphylls varies substantially among authors. A consensus classification for extant (living) species was produced in 2016 by the Pteridophyte Phylogeny Group (PPG I), which places them all in the class Lycopodiopsida, which includes the classes Isoetopsida and Selaginellopsida used in other systems. (See Table 2.) Alternative classification systems have used ranks f ... [...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] |
William Baragwanath
William Baragwanath (1878–1966) was an Australian surveyor, geologist and public servant. In 1922 he was appointed director of the Geological Survey of Victoria, and in 1932 Secretary for Mines. He discovered fossils of ''Baragwanathia'', a genus of extinct plants named in his honour, which at the time was the most ancient land plant known. He was exceptionally knowledgeable about the geology of the Australian state of Victoria. Baragwanath married Clara Ethel, née Jones, on 9 May 1900 at a Presbyterian Church Presbyterianism is a part of the Reformed tradition within Protestantism that broke from the Roman Catholic Church in Scotland by John Knox, who was a priest at St. Giles Cathedral (Church of Scotland). Presbyterian churches derive their nam ... in Flemington. Together they had nine children; seven girls and two boys. He earned his degree at the Ballarat School of Mines. References {{DEFAULTSORT:Baragwanath, William 1878 births 1966 deaths Australian g ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 spor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axil
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of ''Eucalyptus'', palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper (adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll that is essential for photosynthesis as it absorbs light e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microphyll
In plant anatomy and evolution a microphyll (or lycophyll) is a type of plant leaf with one single, unbranched leaf vein. Plants with microphyll leaves occur early in the fossil record, and few such plants exist today. In the classical concept of a microphyll, the leaf vein emerges from the protostele without leaving a leaf gap. Leaf gaps are small areas above the node of some leaves where there is no vascular tissue, as it has all been diverted to the leaf. Megaphylls, in contrast, have multiple veins within the leaf and leaf gaps above them in the stem. Leaf vasculature The clubmosses and horsetails have microphylls, as in all extant species there is only a single vascular trace in each leaf. These leaves are narrow because the width of the blade is limited by the distance water can efficiently diffuse cell-to-cell from the central vascular strand to the margin of the leaf. Despite their name, microphylls are not always small: those of '' Isoëtes'' can reach 25 centimetres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yea Flora Fossil Site
The Yea Flora Fossil Site is a roadside cutting on Limestone Road, Yea, Victoria, Australia. It contains fossils of genus Baragwanathia, some of the world's earliest vascular plants dating back to the begin of the Devonian period, 415 million years ago. The fossils were discovered in 1875, but the significance was not recognized until they were studied in the 1930s by Australian botanist Isabel Cookson. Her work overturned long held scientific understandings of how and when plants evolved. The site is listed on the Australian National Heritage List. See also * List of fossil sites This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of t ... References Australian National Heritage List Paleozoic paleontological sites of Australia Silurian paleontological sites Silurian Austr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isabel Clifton Cookson
Isabel Clifton Cookson (25 December 1893 – 1 July 1973) was an Australian botanist who specialised in palaeobotany and palynology. Early years and education Cookson was born at Hawthorn, Victoria, Hawthorn, Victoria (Australia), Victoria, and attended the Methodist Ladies' College, Melbourne, Methodist Ladies' College at Kew, Victoria, Kew where she gained honours in anatomy, physiology and botany in the senior public examination. Cookson went on to study for her BSc at the University of Melbourne and graduated in 1916 with majors in botany and zoology. Career When she completed her studies she became a demonstrator at the university, and between 1916 and 1917 received a government research scholarship and the James MacBain, MacBain research scholarship in biology, amongst other awards to study the flora of the Northern Territory. She contributed illustrations for the 1917 book ''The Flora of the Northern Territory'' by Alfred J. Ewart and O. B. Davies. She continued work ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graptolite
Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian ( Miaolingian, Wuliuan) through the Lower Carboniferous ( Mississippian). A possible early graptolite, '' Chaunograptus'', is known from the Middle Cambrian. Recent analyses have favored the idea that the living pterobranch '' Rhabdopleura'' represents an extant graptolite which diverged from the rest of the group in the Cambrian. Fossil graptolites and ''Rhabdopleura'' share a colony structure of interconnected zooids housed in organic tubes (theca) which have a basic structure of stacked half-rings (fuselli). Most extinct graptolites belong to two major orders: the bush-like sessile Dendroidea and the planktonic, free-floating Graptoloidea. These orders most likely evolved from encrusting pterobranchs similar to ''Rhabdopleura''. Due to their widespread abundance, pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bryozoa
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a lophophore, a "crown" of tentacles used for filter feeding. Most marine bryozoans live in tropical waters, but a few are found in oceanic trenches and polar waters. The bryozoans are classified as the marine bryozoans (Stenolaemata), freshwater bryozoans (Phylactolaemata), and mostly-marine bryozoans (Gymnolaemata), a few members of which prefer brackish water. 5,869living species are known. At least two genera are solitary (''Aethozooides'' and ''Monobryozoon''); the rest are colonial. The terms Polyzoa and Bryozoa were introduced in 1830 and 1831, respectively. Soon after it was named, another group of animals was discovered whose filtering mechanism looked similar, so it was included in Bryozoa until 1869, when the two groups wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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