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Pentoxylales
Pentoxylales is an extinct order of seed plants known from the Jurassic and Early Cretaceous of East Gondwana. Discovery The first specimens belonging to Pentoxylales were reported by Birbal Sahni in 1948 from Jurassic-Cretaceous strata of the Rajmahal Hills of northeastern India. Remains have subsequently been reported from New Zealand, Australia and Antarctica. The oldest records of the group date to the Upper Jurassic, though there are unconfirmed Early Jurassic records. Morphology Stem The stem of Pentoxylales, referred to by the morphogenus ''Pentoxylon'', consists of 5 or 6 wedge shaped segments embedded within thin walled ground tissue. Leaves Leaves of Pentoxylales are of the strap shaped '' Taenopteris'' morphotype shared with other groups of seed plants, while leaves that preserve the cuticle are referred to the morphogenus '' Nipaniophyllum.'' The leaves are up to 20 centimetres long, and have a prominent midrib. Pollen organs The pollen organs of Pentoxyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentoxylon
Pentoxylales is an extinct order of seed plants known from the Jurassic and Early Cretaceous of East Gondwana. Discovery The first specimens belonging to Pentoxylales were reported by Birbal Sahni in 1948 from Jurassic-Cretaceous strata of the Rajmahal Hills of northeastern India. Remains have subsequently been reported from New Zealand, Australia and Antarctica. The oldest records of the group date to the Upper Jurassic, though there are unconfirmed Early Jurassic records. Morphology Stem The stem of Pentoxylales, referred to by the morphogenus ''Pentoxylon'', consists of 5 or 6 wedge shaped segments embedded within thin walled ground tissue. Leaves Leaves of Pentoxylales are of the strap shaped '' Taenopteris'' morphotype shared with other groups of seed plants, while leaves that preserve the cuticle are referred to the morphogenus '' Nipaniophyllum.'' The leaves are up to 20 centimetres long, and have a prominent midrib. Pollen organs The pollen organs of Pentoxyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages of break-up, involving the separation of Antarctica from South America (forming the Drake Passage) and Australia, occurred during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name (see ), it is also commonly called Gondwanaland. Gondwana was formed by the accretion of several cratons. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of about , about one-fifth of the Earth's surface. During the Carboniferous Period, it merged with Laurasia to form a larger supercontinent called Pangaea. Gondwana (and Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birbal Sahni
Birbal Sahni Royal Society, FRS (14 November 1891 – 10 April 1949) was an Indian paleobotanist who studied the fossils of the Indian subcontinent. He also took an interest in geology and archaeology. He founded what is now the Birbal Sahni Institute of Palaeobotany at Lucknow in 1946. His major contributions were in the study of the fossil plants of India and in plant evolution. He was also involved in the establishment of Indian science education and served as the President of the National Academy of Sciences, India and as an Honorary President of the International Botanical Congress, Stockholm. Formative years Birbal Sahni was born in Bhera, Shahpur, Pakistan, Shahpur District, in today's Pakistani Punjab, on 14 November 1891. He was the third child of Ishwar Devi and the pioneer Indian meteorologist and scientist Lala Ruchi Ram Sahni who lived in Lahore. The family came from Dera Ismail Khan and they frequently made visits to Bhera which was close to the Salt Range and Khew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossopteris
''Glossopteris'' tymology: from Ancient Greek γλῶσσα (glôssa, " tongue ") + πτερίς (pterís, " fern ")is the largest and best-known genus of the extinct Permian order of seed ferns known as Glossopteridales (also known as Arberiales, Ottokariales, or Dictyopteridiales). The genus ''Glossopteris'' refers only to leaves, within a framework of form genera used in paleobotany. (For likely reproductive organs see Glossopteridaceae.) Species of ''Glossopteris'' were the dominant trees of the middle- to high-latitude lowland vegetation across the supercontinent Gondwana during the Permian Period. ''Glossopteris'' fossils were critical in recognizing former connections between the various fragments of Gondwana: South America, Africa, India, Australia, New Zealand, and Antarctica. History The Glossopteridales arose in the Southern Hemisphere around the beginning of the Permian Period (), but became extinct during the end-Permian (Changhsingian) mass extinction. The putat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovule
In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center. The female gametophyte — specifically termed a ''megagametophyte''— is also called the ''embryo sac'' in angiosperms. The megagametophyte produces an egg cell for the purpose of fertilization. The ovule is a small structure present in the ovary. It is attached to the placenta by a stalk called a funicle. The funicle provides nourishment to the ovule. Location within the plant In flowering plants, the ovule is located inside the portion of the flower called the gynoecium. The ovary of the gynoecium produces one or more ovules and ultimately becomes the fruit wall. Ovules are attached to the placenta in the ovary through a stalk-like structure known as a ''funiculus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Plant Orders
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bennettitales
Bennettitales (also known as cycadeoids) is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales are among the most common Mesozoic seed plants, and had morphologies including shrub and cycad-like forms. The foliage of bennettitaleans is superficially nearly indistinguishable from that of cycads, but they are distinguished from cycads by their more complex flower-like reproductive organs, at least some of which were likely pollinated by insects. Although certainly gymnosperms (cone-bearing seed plants), the relationships of bennettitaleans to other seed plants is debated. Their general resemblance to cycads is contradicted by numerous more subtle features of their reproductive systems and leaf structure. Some authors have linked bennettitaleans to angiosperms (flowering plants) and gnetophytes (a rare and unusual group of modern gymnosperms), forming a broader group known as Anth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bramble
A bramble is any rough, tangled, prickly shrub, usually in the genus ''Rubus'', which grows blackberries, raspberries, or dewberries. "Bramble" is also used to describe other prickly shrubs, such as roses (''Rosa'' species). The fruits include blackberries, arctic brambleberries, or raspberries, depending on the species, and are used to make jellies, jams, and preserves. In British English, bramble usually refers to the common blackberry, ''Rubus fruticosus''. ''R. fruticosus'' grows abundantly in all parts of the British Isles, and harvesting the fruits in late summer and autumn is often considered a favourite pastime. An especially hardy plant, bramble bushes can also become a nuisance in gardens, sending down strong suckering roots amongst hedges and shrubs and being particularly resilient against pruning. Many consider ''R. fruticosus'' a weed due its tendency to grow in neglected areas and its sharp, tough thorns, which can be hazardous to children and pets. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liana
A liana is a long- stemmed, woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight. The word ''liana'' does not refer to a taxonomic grouping, but rather a habit of plant growth – much like ''tree'' or ''shrub''. It comes from standard French ''liane'', itself from an Antilles French dialect word meaning to sheave. Ecology Lianas are characteristic of tropical moist broadleaf forests (especially seasonal forests), but may be found in temperate rainforests and temperate deciduous forests. There are also temperate lianas, for example the members of the ''Clematis'' or ''Vitis'' (wild grape) genera. Lianas can form bridges amidst the forest canopy, providing arboreal animals with paths across the forest. These bridges can protect weaker trees from strong winds. Lianas compete with forest trees for sunlight, water and nutrients from the soil. Forests without lian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some reaching several thousand years old. Trees have been in existence for 370 million years. It is estimated that there are some three trillion mature trees in the world. A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk typically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habit (biology)
Habit, equivalent to habitus in some applications in biology, refers variously to aspects of behaviour or structure, as follows: *In zoology (particularly in ethology), habit usually refers to aspects of more or less predictable ''behaviour'', instinctive or otherwise, though it also has broader application. Habitus refers to the characteristic form or morphology of a species. *In botany, habit is the characteristic form in which a given species of plant grows (see plant habit).Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928 Behavior In zoology, ''habit'' (not to be confused with ''habitus'' as described below) usually refers to a specific behavior pattern, either adopted, learned, pathological, innate, or directly related to physiology. For example: * ...the atwas in the ''habit'' of springing upon the oor knockerin order to gain admission... * If these sensitive parrots are kep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) resulting from cross-pollination or allow selfing (fusion of sperm and egg from the same flower) when self-pollination occurs. There are two types of pollination: self-pollination and cross-pollination. Self-pollination occurs when the pollen from the anther is deposited on the stigma of the same flower, or another flower on the same plant. Cross-pollination is when pollen is transferred from the anther of one flower to the stigma of another flower on a different individual of the same species. Self-pollination happens in flowers where the stamen and carpel mature at the same time, and are positi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
