Cyanogranis sp.
Key to families
1. Cells solitary or in mucilaginous colonies, arranged either irregularly or generally oriented in one direction, sometimes forming pseudofilamentous rows, cell division in one plane in successive generations ... Synechococcaceae (Genera included in this volume: Aphanothece, Bacularia, Cyanobacterium, Cyanocatena, Cyanodictyon,Cyanogranis, Cyanonephron, Cyanothece, Epigloeosphaera, Gloeothece, Johannesbaptistia, Lemmermanniella,Myxobaktron, Radiocystis, Rhabdoderma, Rhabdogloea, Synechococcus, Wolskyella)
Key to genera
1. Cells solitary, rarely aggregated into groups ...............................................................................................................2
- Cells forming various colonial aggregations .............................................................................................................. 3
2. Cells with lengthwise striated contents................................................................................................Cyanobacterium
- Cells with reticulate contents ......................................................................................................................Cyanothece
3. Cells in microscopic mucilaginous irregular colonies, at least partly in rows ............................................................4
- Cells within or on the surface of irregularly spherical colonies or in amorphous gelatinous colonies; not in rows....5
4. Colonies spherical or slightly elongated, with cells clustered in the centre and in short radiating rows at the colony periphery ......................................................................................................................................................Radiocystis
- Colonies irregularly-reticulate, composed of mucilaginous pseudofilamentous strands; cells not in radiating rows ........................................Cyanodictyon
5. Colonies containing small, conspicuous and variously shaped ferric precipitates, cells spherical or widely oval..... 6
- Colonies without ferric precipitates, cells oval or rod-shaped, colonies generally amorphous, cells oval or rod-shaped ......................................................7
6. Colonies irregularly spherical, loosely arranged within common mucilage, prominent granular ferric precipitates either within the centre of or on the colony surface...................................................................................Cyanogranis
- Colonies irregular with small ferric precipitates appearing as black ring-like or dot-like granules between adjacent cells or on the surface of cells....................................................................................................................Cyanocatena
7. Colonies with cells irregularly distributed throughout................................................................................................ 8
- Colonies with cells stratified or arranged in different densities in various parts of the colony (i.e. at or near the surface) ....................................................... 9
8. Cells irregularly arranged in colonies, without their own mucilaginous envelopes..................................Aphanothece
- Cells irregularly arranged in colonies, each with their own mucilaginous envelope, usually lamellate and often coloured .........................................Gloeothece
9. Cells situated on or near the surface of gelatinous colonies.......................................................................................10
- Cells situated on the ends of a system of pseudodichotomously branched mucilaginous stalks radiating from the centre of the colony....................Cyanonephron
10. Cells situated on the surface of irregularly spherical to elongated cylindrical to simply divicariate ............................Epigloeosphaera
- Cells situated in one layer under the surface of irregularly spherical colonies.................................Lemmermanniella
Cyanogranis libera Hindák (2002: 417) (Pl. 3F).
Colonies microscopic, gelatinous, spherical to oval or irregular, beginning as a small number of randomly arranged cells, later more, 8–15(–25) μm in diameter, in the centre an irregular to rounded brown ferric body. Cells spherical to oval, 0.8–1.8 μm in diameter, blue-green to pale blue-green in colour, arranged freely in indistinct colonial mucilage, generally distant from ferric body, aerotopes lacking. Mucilage fine, hyaline, 0.5–1.7 μm wide.
Distribution:—Widespread throughout Queensland, found in 50 of the 70 reservoirs and weir pools sampled.
Observations:—The cells in C. libera are not directly connected with the ferric bodies rather freely clustered and slightly distant from them. Ferric bodies are 1–7 μm in diameter and range from smooth, regularly shaped particles, to elongated and sharp edged irregularly shaped granules. Originally described from a Slovakian gravel pit lake in northern Europe, it has a wide distribution throughout north-eastern Australia and is considered widespread in lentic environments. However, it is difficult to ascertain its exact extent given that it is easily confused with other small colonial Chroococcales such as Aphanocapsa which often have organic particles associated with the colonial mucilage, and consequently likely to be under reported.
