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Batrachospermum :Origin ,strucutre ,Thallus organisation and reproduction

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                                              Batrachospermum Occurrence:-   (1) Batrachospermum is fresh water alga.    (2) It is found in clear, cool, and running streams.   (3) Deepwater plants are dark violet or reddish in color. But the shallow-water species are olive green.   (4) The intensity of light changes the color of pigments.   (5) The thallus is attached to the substratum. Vegetative structure  (1) The thallus of an adult plant is soft, thick, filamentous.  (2) It is freely branched and gelatinous.   (3) The central axis is made up of a single row of large cells. Whorls of branches of limited growth        are developed on this axis.  (4) These branches are filamentous and dichotomously arranged.  (5) The main axis is corticated. It consists of a row of elongated cylindrical cells.   (6) It is differentiated into nodes and internodes.   (7) There are two types of branches that arise from the nodes:       Branches of limited growth        Branches of unlimited growth Batra
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Features ,Distribution and Habit of family -Brassicaceae(cruciferae)

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                                        Brassicaceae  Diagnostic feature :- (1) Plants herbs with characterstics pungent sulphur smell. (2) Flowers ebractate,bimerous,hypogynous. (3) Inflorescence corymb or corymbose raceme. (4) Sepals 4,polysepalous,in two whoral of two each. (5) Petals 4,polyandrous,cruciform,uniguiculate. (6) Stemans 6 ,polyandrous,tetradynamous. (7) Gynoecium bicarpellary,syncarpous,ovary superiorbecomes bilocular by a false septum,parietal placentation. (8) Fruit siliqua or silicula. Distribution and habits :-    The family has 375 genera and 3000 species .Plants are cosmopolitian but occur more frequently in colder regions ,plants are mostly herbs,which may be annuals ,biennial or perinnials .Plants have juices due of sulphur containing glucosides. Brasscia napus  (Rapeseeds) Root :-       Tap root system .Primary root may store food (raddish). Stem :-  Herbeceous ,erect,cylindrical rarely,woody,often re
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Habit,Habitat and Distribution-Poaceae Family

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                                          Poaceae Diagnostic Features :- (1) Stem,cylinder,jointed,with generally hollow internodes and intercalary meristems. (2) Leaves ligulate,simple and forms sheathing around base. (3) Flowers arranged in spikelets which in turn are grouped in spike or panicles. (4) Each flower is sessile,bisexual may be unisexual ,zygomorphic,hypogynous. (5) Each flower is covered by scales,That is lemma and plea.The lemma has a stiff awn. (6) Perianth 2-3 called lodicules. (7) Anthers divaricate and versatile. (8) Monocarpellary,ovary superior,unilocular. Distribution and habit:-                                                   It is a family with worldwide distribution.Inindia ,the family is represented by 239 genera and 1180 species. Root :-      Adeventatious root system,stilt roots are present in sugercane and maize to give extra .support. Stem :-   Herbaceous,may be modification to rhizome,stolon or runn
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Ovule,Megasporogenesis and Female Gametophyte

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                Ovule,Megasprogenesis and Female Gametophyte Ovule :-   Ovule is the Megasprangium of angiosprem in which the female gametophyte or embryo  sac develops. Types of Ovule in Angiosperms :-        Orthotropus :-                                It is the basic type of ovule found in angiosperms ,in which micropyle,chalaza and funicle lie in same axis .e.g. Polygonum .       Anatropus :                     In this type ,the nucelleus remains straight .So micropyle,chalaza from a straight line .                    The ovule completely bends along the funicle and gets fused with it to look onverted.e.g.:-Solanacea.            Amphitropus  :-                          In this type ,the body of ovule is bent only halfway so that it comes to lie at right angle to the funicle .                             The fusion of integument and funicle is very little,and so hilum,chalaza and   micropyle lie apart. E.g- Ranaulculacea. Campy
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Steman,Microsporogenesis and development in Anther

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                             Structure of A steman Structure of a Steman :-                                                             In a typical Steman has two part,the long and selender stalk called Filament ,and the  terminal bilobed Anther. The Proximal End of the filament attach to the Thalamus part of the flower..The Size of s teman is Vary from species to species. A typical Angiosperms anther is biolobed and each lobe has two theca .Often longitudnal grooves seperates the theca.The anther is four-sided structure of four microsporangia present in  corner. Structure of a typical steman The microsporangia develops further in to Pollen sacs . Hypodermal Cells of microsporangium called Archesporial Cell and Periclinical division and forms paritial cell and sporogenous cell . Structure of Microsporangium :-                                                                 In transverse section a typical microsporangium appears near circula
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Geological Time Table

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                                 Geological Time Table  Meaning of time Scale: Geological time scale may be a table showing the sequence of earth science periods within the history of earth.  Geological Time Table It additionally shows the lengths of your time totally different earth science periods square measure assumed to own occupied it's measured in a lot of years.  it's been made by learning rock strata, wherever these are exposed by excavations or mining or wherever rivers have cut deeply into the earth’s crust. Scientists have established that lower the rock layer the older it's and therefore the additional ancient square measure the fossils it contains.  With a data of rates of abrasion and deposition, the intervals occupied by totally different periods will be calculable roughly by measure the relative thicknesses of the rock strata. By the technique of radiometric geological dating (i.e. by measure the rates of decay of radioactiv
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