1. CYANOBACTERIA CLASSIFICATION2

2. Background Bergey's Geitle 1925 Fritsch 1942 Desikachary 1959
Fott 1971
Drouet 1981
Smith 1950
Rippka et al., 1979; Castenholz, 2001)
Koma´rek & Anagnostidis, 1989).

3. Cyanobacteria Classification
Order: Chroococcales تضم الطحالب وحيدة الخلية والمستعمرات Order: Chamaesiphonales الطحالب التي تتكاثر بتكوين الجراثيم الداخلية والخارجية Order: Oscillatoriales تضم الخيطية الغير متفرعة والمتفرعة (كاذب او حقيقي)

4. Order: Chroococcales
Family: Chroocaccaceae Chroococcus Gloeocapsa Merismopedia Microcystis بعضها وحيدة الخلية وبعضها مستعمرات ولها جدر سميكة والتكاثر بالإنشطار الثنائي او التفتيت

5. Microcystis
Classification: Empire Prokaryota Kingdom Bacteria Subkingdom Negibacteria Phylum Cyanobacteria Class Cyanophyceae Subclass Oscillatoriophycideae Order Chroococcales Family Microcystaceae Genus Microcystis

6. Microcystis
Unicellular - colonial; colonies gelatinous, free floating or attached to the substrate, microscopic, spherical, discoid or irregular, later usually macroscopic, amorphous, irregular, sometimes net-like, with numerous cells without own mucilaginous envelopes, irregularly distributed within the common slime, sometimes densely agglomerated; colonial mucilage colorless, usually homogeneous, fine, diffluent (staining !), rarely with the limited, sometimes refractive margin. Cells spherical or (after division) hemispherical, with homogeneous, blue-green, greyish or yellowish content, in several planktonic species with several up to numerous aerotopes; sometimes with visible chromatoplasm. Several strains toxic, and producing pcyclocitral. Cell division in 3 planes in successive generations, perpendicular to one another; daughter cells soon separate from one another, and grow into the original size and shape before the next division. Reproduction by the dissociation of colonies. Free floating in plankton of freshwater, more or less eutrophic water reservoirs (sometimes forming heavy water blooms).

7. Order: Chamaesiphonales
تضم اللانواع التي تتكاثر بالجراثيم الداخليه والخارجية واغلبها من العوالق التي تعيش في المياه المالحه Family: Pleurocapsaceae Xenococcus Family: Dermocarpaceae Dermocarpa Family:Chamaesiphonaceae Chamaesiphon

8. Chamaesiphon
Classification: Empire Prokaryota Kingdom Bacteria Subkingdom Negibacteria Phylum Cyanobacteria Class Cyanophyceae Subclass Synechococcophycideae Order Synechococcales Family Chamaesiphonaceae Genus Chamaesiphon

9. Chamaesiphon
Description: Unicellular; solitary, more or less elongated cells or groups of cells joined to the substrate /subg. Chamaesiphon/, or forming microscopic shrub-like colonies or layered, narrow mats with densely and parallel gathered cells on stones or submerged plants, perpendicularly oriented to the substrate /subg. Godlewskia (Janczewski)Geitler 1925/. Cells always polarized, joined to the substrate with one (basal) end by means of a small mucilaginous pad (cells without pads occur only in upper parts of multilayered colonies); cells oval, cylindrical or club-shaped, rounded at the apex. Around cells mucilaginous sheaths, fine and diffluent of firm and lamellated; the sheaths open at the apex during the division process (pseudovaginae). Cell content gray, blue-green or pinkish, usually finely granular, always without aerotopes. Thylakoids localized peripherally, Å concentrically, sometimes, moreover, with several central localized, coiled thylakoids. Cells divide by the transverse fission, usually asymmetrically near the apex; sometimes develop the apical daughter cells (exocytes). Cell division at the apical end can repeat several times. Exocytes are motile and join to the end of opened pseudovaginae or separate completely from the mother cell and attach to the substrate. Only freshwater species growing sessile on aquatic plants, on other algae and on stones, on which they cause sometimes colored (yellow, brown, blackish violet) spots.

10. Order: Oscillatoriales
Family: Oscillatoriaceae Microcoleus, Oscillatoria Family: Nostocaceae Anabaena, Nostoc Family: Riulariaceae Rivularia Family: Scytonemataceae Scytonema, Tolypothrix Family: Stigonemataceae Stigonema

11. Microcoleus
Classification: Empire Prokaryota Kingdom Bacteria Subkingdom Negibacteria Phylum Cyanobacteria Class Cyanophyceae Subclass Oscillatoriophycideae Order Oscillatoriales Family Phormidiaceae Subfamily Microcoleoideae Genus Microcoleus

12. Microcoleus
Description: Filamentous; filaments solitary or joined in fine, thin strata or mats. Filaments composed of a gelatinous, fine, usually colorless and diffluent, homogeneous sheath, in which are densely packed trichomes, arranged parallel and sometimes irregularly screw-like/coiled together; number of trichomes changes usually from 2-3 to more than 100 within one sheath; filaments usually simple, rarely simply branched (only sheaths). Trichomes cylindrical, with straight, usually narrowed ends. Cells usually isodiametric, rarely shorter or longer (to 3 times) than wide; end cells usually conical, rarely with calyptra. (Species with very narrow trichomes and cells always clearly longer than wide and small number of trichomes within sheaths probably belong to a special genus of Schizothrichaceae). Cell division crosswise, daughter cells grow into the original size before the next division. Reproduction by motile fragments of trichomes or hormogonia; fragmentation usually by help of necridic cells. Mainly benthic and soil species, covering the substrate or growing in psammon under a slight layer of wet sand. Several species known from sandy and muddy marine beaches and river estuaries or from other types of sea coasts or inland saline biotopes. Several species are known from wet soil or from littoral of clear or slightly polluted water bodies, where they cover mud or acquatic plants. Known also from wet rocks and mineral springs.

13. Cyanobacteria Reproduction
Reproduction Like bacteria, the cyanobacteria also reproduce asexually and the commonest mode of reproduction in them in transverse binary fission (see bacteria). In addition, there are certain specialized structures such as akinetes, hormogonia, hormocysts and spores, which are partly involved in the process of reproduction.

14. Binary Fission
Binary fission
is the subdivision of a body, population, or species into parts and the regeneration of those parts into separate individuals.

15. Akinetes
Akinetes
Akinetes Most filamentous cyanobacteria develop perennating (dormant structures) in adverse condition. These structures are larger than the vegetative cells, are equipped with thick walls, and are called akinetes . When favourable conditions return, they germinate and produce new filaments.

16. Hormogonia Hormogonia
Hormogonia All filamentous Cyanobacterium reproduce by fragmentation of their filaments (trichomes) at more or less regular intervals to form short pieces each consisting of 5-15 cells. These short pieces of filaments are called hormogonia. The latter show gliding motility and develop into new full-fledged filaments

17. Hormocysts Hormocysts
Hormocysts Some cyanobacterial produce hrormocysts, which are multicellular structures having a thick and massive sheath. They may be intercalary or terminal in position and may germinate from either end or both the ends to give rise to the new filaments

18. Spores
Endospores are produced endogenously like those in bacteria; exospores are the result to exogenous budding of cells, and the nanocysts are produced endogenously like endospores. The difference between an endospore and a nanocysts is that in endospore formation the parent cell concomitantly enlarges in size, whereas in nanocysts formation there is no such enlargement of the cell.

19. False Branching
In bacteriology, the appearance of branching produced when a cell is pushed out of the general line of growth and develops a new line of growth while the remaining cells continue to develop along the original line of growth

20. True Branching
Filaments made of several cells in width forming branches by the division of cellsperpendicularly to the main filament axis (true branching).