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Fern Genera
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase. Ferns have complex leaves called megaphylls that are more complex than the microphylls of clubmosses. Most ferns are leptosporangiate ferns. They produce coiled fiddleheads that uncoil and expand into fronds. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the Polypodiopsida, comprising both the leptosporangiate ( Polypodiidae) and eusporangiate ferns, the latter group including horsetails, whisk ferns, marattioid ferns, and ophioglossoid ferns. The fern crown group, consisting of the leptosporangiates and eusporangiates, is estimated to have originated in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago (Megaannum, Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of history of life#Colonization of land, life on land occurred during the Devonian, as free-spore, sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaf, leaves and true roots, and by the end of the period the first seed-bearing plants (Pteridospermatophyta, pteridospermatophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylem
Xylem is one of the two types of transport tissue (biology), tissue in vascular plants, the other being phloem; both of these are part of the vascular bundle. The basic function of the xylem is to transport water upward from the roots to parts of the plants such as stems and leaves, but it also transports plant nutrition, nutrients. The word ''xylem'' is derived from the Ancient Greek word (), meaning "wood"; the best-known wood organism is plants, though it is found throughout a plant. The term was introduced by Carl Nägeli in 1858. Structure The most distinctive xylem cell (biology), cells are the long tracheary elements that transport water. Tracheids and vessel elements are distinguished by their shape; vessel elements are shorter, and are connected together into long tubes that are called ''vessels''. Wood also contains two other type of cells: Ground tissue#Parenchyma, parenchyma and ground tissue#Fibres, fibers. Xylem can be found: * in vascular bundles, present in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiddlehead Fern
Fiddleheads or fiddlehead greens are the furled fronds from a fledgling fern, harvested for use as a vegetable. Left on the plant, each fiddlehead would unroll into a new frond ( circinate vernation). As fiddleheads are harvested early in the season, before the frond has opened and reached its full height, they are cut fairly close to the ground. Fiddleheads from brackens contain ptaquiloside, a compound associated with bracken toxicity, and thiaminase. Not all species contain ptaquiloside, such as '' Diplazium esculentum'', a fern with fiddleheads regularly consumed in parts of East Asia, which differs from bracken ('' Pteridium aquilinum''). The fiddlehead resembles the curled ornamentation (called a ''scroll'') on the end of a stringed instrument, such as a fiddle. It is also called a crozier, after the curved staff used by bishops, which has its origins in the shepherd's crook. Varieties The fiddleheads of certain ferns are eaten as a cooked leaf vegetable. The m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptosporangiate Fern
The Polypodiidae, commonly called leptosporangiate ferns, formerly Leptosporangiatae, are one of four subclasses of ferns, the largest of these being the largest group of living ferns, including some 11,000 species worldwide. The group has also been treated as the class Pteridopsida or Polypodiopsida, although other classifications assign them a different rank. Older names for the group include Filicidae and Filicales, although at least the "water ferns" (now the Salviniales) were then treated separately. The leptosporangiate ferns are one of the four major groups of ferns, with the other three being the eusporangiate ferns comprising the marattioid ferns (Marattiidae, Marattiaceae), the horsetails (Equisetiidae, Equisetaceae), and whisk ferns and moonworts. There are approximately 8465 species of living leptosporangiate ferns, compared with about 2070 for all other ferns, totalling 10535 species of ferns. Almost a third of leptosporangiate fern species are epiphytes. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clubmosses
Lycopodiopsida is a class of vascular plants also known as lycopsids, lycopods, or lycophytes. 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 ( Lepidodendrales) 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 from div ... [...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 centimetr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaf
A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the Shoot (botany), shoot system. In most leaves, the primary Photosynthesis, photosynthetic Tissue (biology), 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. The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper (Glossary of botanical terms#adaxial, adaxial) and lower (Glossary of botanical terms#abaxial, abaxial) surfaces that differ in color, Trichome, hairiness, the number of stomata (pores that intake and output gases), the amount and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DK Pub
DK (or variants) may refer to: In arts and entertainment Film and television * ''DK'' (film), a 2015 Indian film * Derek "DK" Kitson, a character in the television series ''Third Watch'', played by Derek Kelly * Dark Kingdom (professional wrestling), a professional wrestling stable * Discovery Kids Music * DK (band), a Soviet rock band * DK (singer), South Korean singer and member of Seventeen * Deekay, a music production team * Danity Kane, an American female music group * Darren Knott, British disc jockey and record producer * Dave Koz, American saxophonist * Dead Kennedys, American punk band Other media * Diels–Kranz numbering, a standard system for referencing the works of the pre-Socratic philosophers * Donkey Kong (character), a video game character * Diddy Kong, a video game character * Dixie Kong, a video game character * DistroKid, an American independent digital music service Businesses and organizations * DK (publisher) (Dorling Kindersley), an internat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporophyte
A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spore, spores. This stage Alternation of generations, alternates with a multicellular haploid gametophyte phase. Life cycle The sporophyte develops from the zygote produced when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell therefore has a double set of chromosomes, one set from each parent. All Embryophyta, land plants, and most multicellular algae, have life cycles in which a multicellular diploid sporophyte phase alternates with a multicellular haploid gametophyte phase. In the Spermatophyte, seed plants, the largest groups of which are the gymnosperms (bare seeds) and angiosperms (fruiting plants), the sporophyte phase is more prominent than the gametophyte, and is the familiar green plant with its roots, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moss
Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryophytes, which comprise Marchantiophyta, liverworts, mosses, and hornworts. Mosses typically form dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple leaf, leaves that are generally only one cell thick, attached to a plant stem, stem that may be branched or unbranched and has only a limited role in conducting water and nutrients. Although some species have conducting tissues, these are generally poorly developed and structurally different from similar tissue found in vascular plants. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing sporangium, spores. They are typically tall, though some species ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flower
Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, modified leaves; corolla, the petals; androecium, the male reproductive unit consisting of stamens and pollen; and gynoecium, the female part, containing style and stigma, which receives the pollen at the tip of the style, and ovary, which contains the ovules. When flowers are arranged in groups, they are known collectively as inflorescences. Floral growth originates at stem tips and is controlled by MADS-box genes. In most plant species flowers are heterosporous, and so can produce sex cells of both sexes. Pollination mediates the transport of pollen to the ovules in the ovaries, to facilitate sexual reproduction. It can occur between different plants, as in cross-pollination, or between flowers on the same plant or even the same f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
