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Home >> Botany Dictionary >> Bracket Fungi-Buttress Root
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Bracket Fungi - The members of order Sphyllophorales (Polyporales) of Hymenomycetes that are producing large basidiocarps which rarely have gills. These include polypores which grow out in a bracket like manner from both living and dead wood e.g., Payporus squamosus.
Bract - A leaf like organ which is extending an inflorescence. It is sometimes brightly coloured and peral like e.g., in Euphorbia pulcherrima.
Bracteole - A leaf, generally small, present on a flower stalk.
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Bracteomania - Used for abnormal production of large numbers of bracts, generally at the expense of normal flowers.
Bradytelic - Used in chronistics, to describe a species that has remained more or less unchanged for millions of years. Examples of bradytelic are certain gymnosperms like Podocarpous Girkgo and Welwilschia. Evidence of such nature of these plants comes from studies of fossils and karyotypes of these plants.
Brand Spore - A thick walled resting spore which is formed by the Ustilaginales. They are dark coloured and found in sooty masses.
Braun-Blanquet Scheme - A method of describing an area of vegetation devised by J. Braun Blanquet in 1927. It is used to survey large areas rapidly. Two scales are used, one employs+sign and umbers from 1 to 5 denoting both the number of species and the proportion of area covered by the species ranging from+(sparse and covering a small area) to 5 (covering more than 75 per cent of the area).
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Other scale employs how the species are around and ranges from class Soc. I (growing singly) to Soc. 5 (growing in pure populations.) It is possible to obtain information by laying down adjacent quadrats of increasing size. A scale for expressing degrees of presence of population is also included in which 5=constantly present in 80-100 percent of the areas and l=rare i.e., in 1-20 percent areas only.
Breaking of Meres - The sudden development of large masses of blue green algae in small masses of fresh water.
Breathing Root - A root which is produced by large plants growing in mud; it projects above the mud and water allowing the air to reach the root below.
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Brochidodromous (See camptodromous) - Used for describing the venation in which there is a single primary vein and the secondary veins are rising from it curve upwards towards leaf margin and join together in a series of conspicuous loops at the margin e.g., in Prunusaviun.
Brown Algae - Members of Phaephayta. These are predonantly marine vegetative organisation is more advanced relatively, cell wall has alginic and fucinic acids characteristically, cytoplasm has fucosan vesicles. The sexual reproduction is usually oogamus.
Brown Earth - A soil formed on loams and clays, having a fairly low air content. Though it is typically acid, the amount of exchange calcium has been fairly high.
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Brownian Movement - The continuous movements of the particles in a colloidal solution. It is caused by the unbalanced bombardment with the molecules of the liquid.
Bryokinin - A growth substance which is found in certain mosses e.g. Funaria, which stimulates formation of buds and subsequently leafy plants from fillamentous protonema.
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Bud. A compacted stem having leaves and sometimes flowers. This gets elongated to produce the mature shoot and its attached organs.
Budding - (i) The production of buds in organs.
(ii) Grafting a bud from a stock to a scion.
(iii) The asexual reproduction of unicellular fungi, e.g., yeasts. or spores, by the development of a new cell from the outgrowth of the parent.
Bulb - An organ of storage and vegetative reproduction. It conxils, and scale leaves.
Bulbil - (i) A small bulb.
(ii) Out growths on the stem of some species of Lycopodium which are functioning for vegetative reproduction. They are probably modified leave
s.
(iii) An organ of asexual reproduction which is produced on the rhizoids of the Charales.
(iv) A small sclerotium-like body, of a few cells produced by some fungi.
Bulliform Cells. (motor cells). Any of the large cells occurring at places in longitudinal rows in leaf epidermis of rolling xerophytes (that show rolling of lamina in dryness) which are mostly grasses. These cells are involved in rolling and unrolling of lamina due to rapid loss and reabsorption of water during dry and wet conditions respectively.
Bundle Cap. One or more layers of sclerenchyma on thickened parenchyma cells over the xylem or phloem or both poles of a vascular bundle. It occurs in certain plants only.
Bundle Sheath - The sheath of parenchyma surrounding the vascular bundle of a leaf. The elongated cells conduct materials between the nundle and the leaf parenchyma.
Bunt - A covered smut disease of wheat. It is sometimes celled stiking smut due to smell of rotten fish given off by the spore mass of infecting fungus Telletia caries. Dwarf bunt of wheat has been caused by T. contraversa. Infected grains are trans formed into balls of bunt spores. At the time of threshing these spores are spread to healthy seeds.
Bur (burr) - A type of pseudocarp in which fruit has been covered by a persistant barbed involucre as in Arctium and Xanthium.
Burgundy Mixture - A fungicide which is similar to Bordeaux mixture, but sodium carbonate has replaced the lime.
Butterfly Flower - A flower pollinated by butterflies.
Button - The young fructification of an agaric, before the cap gets broken away from the stipe, and the pileus gets exposed.
Buttress Root - A root, generally adventitious and above ground, imparting additional support to the stem or trunk.
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