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Vexatorella Obtusata Obtusata Rebelo 2
'' Vexatorella '' is a genus containing four species of flowering plant, commonly known as vexators, in the family Proteaceae. The genus is endemic to the Cape Floristic Region of South Africa. The name means “little trouble-maker”, given with reference to the initial difficulties of placing ''V. latebrosa'' within the family. All species are shrubs which occur in dry fynbos habitats on the fringes of the Succulent Karoo ecoregion. The inflorescences are similar to those of the related leucospermums but also share features of the leucadendrons, with the floral bracts becoming woody and enlarged following pollination. The flowers are insect-pollinated, with the seeds dispersed by ants (myrmecochory). Description Vexators are upright or spreading evergreen shrubs with alternately set, narrow, spade-shaped leaves ending bluntly in a bony tip, with an entire margin, and greyish or bluish in colour. The stalked flower heads are mostly set individually, sometimes wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Patrick Rourke
John Patrick Rourke FMLS (born 26 March 1942, in Cape Town) is a South African botanist, who worked at the Kirstenbosch National Botanical Garden and became curator of the Compton Herbarium. He is a specialist in the flora of the Cape Floristic Region, in particular the family Proteaceae. Career Rourke studied at the University of Cape Town from 1960 to 1970, where he obtained his B.Sc., M.Sc. and Ph.D. He started working at Kirstenbosch from 1966, and succeeded Winsome Fanny Barker as curator of the Compton Herbarium in 1972. He published several revisions of Proteacean genera including ''Leucadendron'', '' Leucospermum'', '' Mimetes'', '' Vexatorella'', ''Sorocephalus'' and '' Spatalla''. During his career he collected approximately 2000 specimens of flora from the southwestern and southern Cape, Namaqualand and eastern Transvaal. In 1997 he was made foreign member of the Linnean Society of London. In 2003 Rourke was awarded the "Gold medal for Lifetime Preservation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myrmecochory
Myrmecochory ( (sometimes myrmechory); from grc, μύρμηξ, mýrmēks ("ant") and ''khoreíā'' ("circular dance") is seed dispersal by ants, an ecologically significant ant–plant interaction with worldwide distribution. Most myrmecochorous plants produce seeds with elaiosomes, a term encompassing various external appendages or "food bodies" rich in lipids, amino acids, or other nutrients that are attractive to ants. The seed with its attached elaiosome is collectively known as a diaspore. Seed dispersal by ants is typically accomplished when foraging workers carry diaspores back to the ant colony, after which the elaiosome is removed or fed directly to ant larvae. Once the elaiosome is consumed, the seed is usually discarded in underground middens or ejected from the nest. Although diaspores are seldom distributed far from the parent plant, myrmecochores also benefit from this predominantly mutualistic interaction through dispersal to favourable locations for g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Locule
A locule (plural locules) or loculus (plural loculi) (meaning "little place" in Latin) is a small cavity or compartment within an organ or part of an organism (animal, plant, or fungus). In angiosperms (flowering plants), the term ''locule'' usually refers to a chamber within an ovary (gynoecium or carpel) of the flower and fruits. Depending on the number of locules in the ovary, fruits can be classified as ''uni-locular'' (unilocular), ''bi-locular'', ''tri-locular'' or ''multi-locular''. The number of locules present in a gynoecium may be equal to or less than the number of carpels. The locules contain the ovules or seeds. The term may also refer to chambers within anthers containing pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop .... In Ascomycete fungi, locules are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carpel
Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils'' and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the " female" portion of the flower, although rather than directly producing female gametes (i.e. egg cells), the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells. The term gynoecium is also used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses, liverworts, and hornworts. The corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens are call ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovary (botany)
In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule(s) and is located above or below or at the point of connection with the base of the petals and sepals. The pistil may be made up of one carpel or of several fused carpels (e.g. dicarpel or tricarpel), and therefore the ovary can contain part of one carpel or parts of several fused carpels. Above the ovary is the style and the stigma, which is where the pollen lands and germinates to grow down through the style to the ovary, and, for each individual pollen grain, to fertilize one individual ovule. Some wind pollinated flowers have much reduced and modified ovaries. Fruits A fruit is the mature, ripened ovary of a flower following double fertilization in an angiosperm. Because gymnosperms do not have an ovary but reproduce through double fertilization of unprotected ovules, they produce naked seeds that do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen Presenter
A pollen-presenter is an area on the tip of the style in flowers of plants of the family Proteaceae on which the anthers release their pollen prior to anthesis. To ensure pollination, the style grows during anthesis, sticking out the pollen-presenter prominently, and so ensuring that the pollen easily contacts the bodies of potential pollination vectors such as bees, birds and nectarivorous mammals. The systematic depositing of pollen on the tip of the style implies the plants have some strategy to avoid excessive self-pollination Self-pollination is a form of pollination in which pollen from the same plant arrives at the stigma of a flower (in flowering plants) or at the ovule (in gymnosperms). There are two types of self-pollination: in autogamy, pollen is transferred t .... References * Plant anatomy + Proteaceae {{Botany-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stigma (botany)
The stigma () is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower. Description The stigma, together with the style and ovary (typically called the stigma-style-ovary system) comprises the pistil, which is part of the gynoecium or female reproductive organ of a plant. The stigma itself forms the distal portion of the style, or stylodia, and is composed of , the cells of which are receptive to pollen. These may be restricted to the apex of the style or, especially in wind pollinated species, cover a wide surface. The stigma receives pollen and it is on the stigma that the pollen grain germinates. Often sticky, the stigma is adapted in various ways to catch and trap pollen with various hairs, flaps, or sculpturings. The pollen may be captured from the air (wind-borne pollen, anemophily), from visiting insects or other animals (biotic pollination), or in rare cases from surrounding water ( hydrophily). Stigma can vary from long and sle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perianth
The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when called a perigone. The term ''perianth'' is derived from Greek περί (, "around") and άνθος (, "flower"), while ''perigonium'' is derived from περί () and γόνος (, "seed, sex organs"). In the mosses and liverworts (Marchantiophyta), the perianth is the sterile tubelike tissue that surrounds the female reproductive structure (or developing sporophyte). Flowering plants In flowering plants, the perianth may be described as being either dichlamydeous/heterochlamydeous in which the calyx and corolla are clearly separate, or homochlamydeous, in which they are indistinguishable (and the sepals and petals are collectively referred to as tepals). When the perianth is in two whorls, it is described as biseriate. While the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Reproductive Morphology
Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants (green algae, mosses, liverworts, hornworts, ferns and gymnosperms such as conifers) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floral Symmetry
Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirally arranged. Actinomorphic Most flowers are actinomorphic ("star shaped", "radial"), meaning they can be divided into 3 or more identical sectors which are related to each other by rotation about the center of the flower. Typically, each sector might contain one tepal or one petal and one sepal and so on. It may or may not be possible to divide the flower into symmetrical halves by the same number of longitudinal planes passing through the axis: Oleander is an example of a flower without such mirror planes. Actinomorphic flowers are also called radially symmetrical or regular flowers. Other examples of actinomorphic flowers are the lily (''Lilium'', Liliaceae) and the buttercup (''Ranunculus'', Ranunculaceae). Zygomorphic Zygom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merosity
Merosity (from the greek "méros," which means "having parts") refers to the number of component parts in a distinct whorl of a plant structure. The term is most commonly used in the context of a flower where it refers to the number of sepals in a whorl of the calyx, the number of petals in a whorl of the corolla, the number of stamens in a whorl of the androecium, or the number of carpels in a whorl of the gynoecium. The term may also be used to refer to the number of leaves in a leaf whorl. The adjective ''n''-merous refers to a whorl of ''n'' parts, where ''n'' is any integer greater than one. In nature, five or three parts per whorl have the highest frequency of occurrence, but four or two parts per whorl are not uncommon. Be aware that two consecutive whorls of dimerous petals are often mistaken for tetramerous petals. If all of the whorls in a given floral arrangement have the same merosity, the flower is said to be isomerous, otherwise the flower is anisomerous. For exam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peduncle (botany)
In botany, a peduncle is a stalk supporting an inflorescence or a solitary flower, or, after fecundation, an infructescence or a solitary fruit. The peduncle sometimes has bracts (a type of cataphylls) at nodes. The main axis of an inflorescence above the peduncle is the rachis. There are no flowers on the peduncle but there are flowers on the rachis. When a peduncle arises from the ground level, either from a compressed aerial stem or from a subterranean stem (rhizome, tuber, bulb, corm), with few or no bracts except the part near the rachis or receptacle, it is referred to as a scape. The acorns of the pedunculate oak ''Quercus robur'', commonly known as common oak, pedunculate oak, European oak or English oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe west of the Caucasus. It is wid ... are borne on a long peduncle, hence the name of the tree. See also * Pedicel (botany) * Scape (botany) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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