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Aceria Fraxini
''Aceria fraxini'', the ash bead gall mite, is a species of mites in the family Eriophyidae, the gall mites. Ecology Range is North America, including southern Canada and most of the continental United States. Mites form numerous capsule galls, greenish-yellow in color, between leaf veins of Ash trees in the genus ''Fraxinus'', including ''Fraxinus americana'', ''Fraxinus latifolia'', ''Fraxinus nigra'', and ''Fraxinus pennsylvanica''. The mites stay in the galls until late summer when host leaves mature. The life cycle is a form of alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of Biological life cycle, life cycle in plants and algae. It consists of a Multicellular organism, multicellular haploid sexual phase, the gametophy .... An over-wintering generation consists only of females called deutogynes. The other generation consists of both sexes: females called protogynes as well as males. Referen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samuel Garman
Samuel Walton Garman (June 5, 1843 – September 30, 1927), or "Garmann" as he sometimes styled himself, was a naturalist/zoologist from Pennsylvania. He became noted as an ichthyologist and herpetologist. Biography Garman was born in Indiana County, Pennsylvania, on 5 June 1843. In 1868 he joined an expedition to the American West with John Wesley Powell. He graduated from the Illinois State Normal University in 1870, and for the following year was principal of the Mississippi State Normal School. In 1871, he became professor of natural sciences in Ferry Hall Seminary, Lake Forest, Illinois, and a year later became a special pupil of Louis Agassiz. He was a friend and regular correspondent of the naturalist Edward Drinker Cope, and in 1872 accompanied him on a fossil hunting trip to Wyoming. In 1870 he became assistant director of herpetology and ichthyology at Harvard's Museum of Comparative Zoology. His work was mostly in the classification of fish, especially sharks, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraxinus Americana
''Fraxinus americana'', the white ash or American ash, is a species of '' ash tree'' native to eastern and central North America. The species is native to mesophytic hardwood forests from Nova Scotia west to Minnesota, south to northern Florida, and southwest to eastern Texas. Isolated populations have also been found in western Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ..., Wyoming, and Colorado, and the species is reportedly naturalized in Hawaii. There are an estimated 8 billion ash trees in the United States – the majority being the white ash trees and the Fraxinus pennsylvanica, green ash trees. Characteristics The name white ash derives from the glaucous undersides of the leaves. It is similar in appearance to the green ash, making identification difficult. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropods Of The United States
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arthropod cuticle, cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an exoskeleton, external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior Organ (anatomy), organs; it has an open circulatory system. Like their exteriors, the internal or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropods Of Canada
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is "ladder-lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protogyny
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, a sequential hermaphrodite produces eggs (female gametes) and sperm (male gametes) at different stages in life. Species that can undergo these changes from one sex to another do so as a normal event within their reproductive cycle that is usually cued by either social structure or the achievement of a certain age or size. In animals, the different types of change are male to female (protandry or protandrous hermaphroditism), female to male (protogyny or protogynous hermaphroditism), bidirectional (serial or bidirectional hermaphroditism). Both protogynous and protandrous hermaphroditism allow the organism to switch between functional male and functional female. Bidirectional hermaphrodites have the capacity for sex change in either directi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternation Of Generations
Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of Biological life cycle, life cycle in plants and algae. It consists of a Multicellular organism, multicellular haploid sexual phase, the gametophyte, which has a single set of chromosomes alternating with a multicellular diploid asexual phase, the sporophyte which has two sets of chromosomes. A mature sporophyte produces haploid spores by meiosis, a process which reduces the number of chromosomes to half, from two sets to one. The resulting haploid spores germinate and grow into multicellular haploid gametophytes. At maturity, a gametophyte produces gametes by mitosis, the normal process of cell division in eukaryotes, which maintains the original number of chromosomes. Two haploid gametes (originating from different organisms of the same species or from the same organism) fertilisation, fuse to produce a diploid zygote, which divides repeatedly by mitosis, developing into a multice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraxinus Pennsylvanica
''Fraxinus pennsylvanica'', the green ash or red ash, is a species of ash native to eastern and central North America, from Nova Scotia west to southeastern Alberta and eastern Colorado, south to northern Florida, and southwest to Oklahoma and eastern Texas. It has spread and become naturalized in much of the western United States and also in Europe from Spain to Russia. Other names more rarely used include downy ash, swamp ash and water ash. Description ''Fraxinus pennsylvanica'' is a medium-sized deciduous tree reaching (rarely to ) tall with a trunk up to in diameter. The bark is smooth and gray on young trees, becoming thick and fissured with age. The winter buds are reddish-brown, with a velvety texture. The leaves are long, oppositely arranged, pinnately compound with seven to nine (occasionally five or eleven) leaflets, these (rarely ) long and broad, with serrated margins and short but distinct, downy petiolules a few millimeters long. They are green both above ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraxinus Nigra
''Fraxinus nigra'', the black ash, is a species of ash native to much of eastern Canada and the northeastern United States, from western Newfoundland west to southeastern Manitoba, and south to Illinois and northern Virginia. Formerly abundant, as of 2014 the species is threatened with near total extirpation throughout its range, as a result of infestation by a parasitic insect known as the emerald ash borer. Description Black ash is a medium-sized deciduous tree reaching (exceptionally ) tall with a trunk up to diameter, or exceptionally to . The bark is grey, thick and corky even on young trees, becoming scaly and fissured with age. The winter buds are dark brown to blackish, with a velvety texture. The leaves are opposite, pinnately compound, with 7–13 (most often 9) leaflets; each leaf is long, the leaflets long and broad, with a finely toothed margin. The leaflets are sessile, directly attached to the rachis without a petiolule. The flowers are produced in sprin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraxinus Latifolia
''Fraxinus latifolia'', the Oregon ash, is a member of the ash genus '' Fraxinus'', native to western North America. Description ''Fraxinus latifolia'' is a medium-sized deciduous tree that can grow to heights of in height, with a trunk diameter of in its 100−150-year average life span. Oregon ash can grow considerably larger and can have well over a 200-year life span, or become stunted and very small in more dry habitats. It can develop a broad crown, almost as wide as a bigleaf maple (''Acer macrophyllum'') when it grows in the open, but crowns remain narrow when they are part of a denser tree stand, similar to that of red alder (''Alnus rubra''). The bark is distinctive with dark gray–brown, and it will eventually develop a woven pattern of deep fissures and ridges. The compound leaves are pinnate, long, with 5–9 leaflets attached in pairs to a linear stalk and an additional leaflet at the tip. Each leaflet is ovate, long and broad. The leaves are noticeably lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraxinus
''Fraxinus'' (), common name, commonly called ash, is a genus of flowering plants in the olive and lilac family, Oleaceae. It contains 45–65 species of usually medium to large trees, mostly deciduous, though a number of Subtropics, subtropical species are evergreen. The genus is widespread across much of Europe, Asia, and North America. The leaf, leaves are opposite leaves, opposite (rarely in Whorl (botany), whorls of three), and mostly pinnate, pinnately compound, though simple in a few species. The seeds, popularly known as "keys" or "helicopter seeds", are a type of fruit known as a samara (fruit), samara. Some ''Fraxinus'' species are Dioecy, dioecious, having male and female flowers on separate plants but sex in ash is expressed as a continuum between male and female individuals, dominated by unisexual trees. With age, ash may change their sexual function from predominantly male and hermaphrodite towards femaleness ; if grown as an ornamental and both sexes are present, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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