IDs have been checked against "The Freshwater Algal Flora of the British Isles" (FAFBI. Some older IDs done using "How to Know the Freshwater Algae" (Prescott).
Question marks (?) added where ID is uncertain.
| Name | Image Links | Description |
|---|---|---|
| Geminella | 1 2 3 4 5 6 7 8 9 | filamentous Chlorophyte: cells usually in pairs within a mucilage sheath, with a parietal band chloroplast. |
| Geminella interrupta | 1 | |
| Geminella mutabilis | 1 2 | |
| Glaucocystis | 1 | Eucaryotic cell with blue-green cyanelles (normally ribbon-shaped) instead of chloroplasts. |
| Gloeocapsa | 1 2 | colonial Cyanobacterium: cells in a lamellate mucilage growing attached to surfaces |
| Gloeocystis | 1 2 3 4 5 6? 7 8 9 10 11 12 | colonial Chlorophyte: oval or spherical cells in concentrically layered mucilage, chloroplast cup-shaped. |
| Gloeocystis vesiculosa | 1 2 3 4 5 6 7 8 9 10 | colonial Chlorophyte: oval or spherical cells in concentrically layered mucilage, chloroplast cup-shaped. |
| ?Gloeotila subconstricta | 1 | filamentous chlorophyte |
| Gloeotrichia | 1 | colonial Cyanobacterium: tapering filaments with a basal heterocyst, attached to surfaces, vegetation, etc., forming a subspherical tuft |
| Gomphonema acuminatum | 1 2 3 | Diatom: elongated cells, attached to surfaces by a branched stalk, cells broader at distal end. |
| Gomphonema subtile | 1 | |
| Gomphonema truncatum | 1 2 3 4 5 6 7 | |
| Gomphosphaeria | 1 2 3 | colonial Cyanobacterium:cells usually seen as heart-shaped, in mucilage at the end of branching stalks |
| Gomphosphaeria aponina | 1 2 3 4 | |
| Gonatozygon kinahanii | 1 2 3 4 5 | filamentous Desmid: elongated cells usually in pairs joined end-to-end, ends slightly swollen, cell surface decorated, chloroplast axile. |
| Gonatozygon monotaenium | 1 2 3 4 | |
| Groenbladia neglecta | 1 | filamentous Desmid |
| Gymnodinium aeruginosum | 1 | Pyrrophyte with blue-green cyanelles |
| Gyrosigma acuminatum | 1 2 3 4 5 6 7 8 | Diatom: sigmoid, tapering shape |
| Gyrosigma attenuatum | 1 | |
| Gyrosigma ?spencerii | 1 2 |
| Name | Image Links | Description |
|---|---|---|
| Haematococcus | 1 2 3 4 5 6 | unicellular Chlorophyte: common in bird-baths; green or red flagellate cell in vegetative state, but forms red spherical cysts when the habitat dries out. |
| Hannaea arcus | 1 2 | Diatom: banana-shaped frustule with capitate ends. |
| Hapalosiphon | 1 2 3 4 | filamentous Cyanobacterium: main axis has branches arising at right angles, cells blue-green, sometimes forming more than 1 series; sheath may be darkened |
| Haplotaenium minutum | 1 2 | Desmid: straight baton-shaped cell with a median constriction but no basal inflation (unlike Pleurotaenium), 1 ridged chloroplast in each semicell |
| Heterococcus viridis | 1 | filamentous Xanthophyte: branched filament, cells with numerous bright green plate-like chloroplasts |
| Homoeothrix | 1 2 3 4 5 6 7 | filamentous Cyanobacterium: sheathed, tapering trichome, false branching, no heterocysts (cf. Tolypothrix) |
| Hormidium | Descriptive notes. | filamentous Chlorophyte: long unbranched filaments which tend to kink frequently: cells square- to long-cylindric with a (usually) disc-shaped chloroplast which wraps round about half the cell circumference and nearly as long as the cell, otherwise very similar to Ulothrix. |
| Hormidium (Klebsormidium) | 1 2 3 4 5 6 7 8 | |
| Hormidium subtile | 1 | |
| ?Hormotila mucigena | 1 2 3 4 5 6 | filamentous Chlorophyte: cells at the end of or at intervals along the length of branching mucilage tubes; the tubes may be featureless or show layering. Chloroplasts net-like: this is not evident in these pictures. |
| Hyalotheca dissiliens | 1 2 3 4 5 6 7 8 9 | filamentous Chlorophyte (Desmid):cells have a median incision, giving the filament an uneven appearance: single stellate chloroplast; the filament can sometimes be seen to have a wide mucilage sheath with radiating fibrils. |
| Hyalotheca mucosa | 1 | |
| Hydrodictyon | 1 2 3 4 : inspiration for the 'Algal Web' | colonial Chlorophyte: cylindrical cells are linked at each end to 2 others to form a net-like structure; each cell grows larger and eventually a smaller net forms inside. |
| Name | Image Links | Description |
|---|---|---|
| Keratococcus bicaudatus | 1 | Unicellular chlorophyte |
| Kirchneriella | 1 2 3 | colonial Chlorophyte: small, crescent- or comma-shaped cells in small groups within a mucilaginous sheath |
| Kirchneriella aperta | 1 | |
| Klebsormidium (Hormidium) | 1 2 3 4 | filamentous Chlorophyte: long unbranched filaments which tend to kink frequently: cells square- to long-cylindric with a (usually) disc-shaped chloroplast which wraps round about half the cell circumference and about as long as the cell, otherwise very similar to Ulothrix. |
| Klebsormidium crenulatum | 1 2 3 | |
| Korshikoviella mikhailovskoensis | 1 2 3 4 | Spindle-shaped green cell, frequently attached at one end with a spine at the other, with a segmented chloroplast. |
| Name | Image Links | Description |
|---|---|---|
| Lemanea | 1 2 3 4 5 6 7 8 9 10 11 | filamentous Rhodophyte: grey, olive-green or brown in colour, multiseriate, branching may be infrequent, but filaments are tapering with swollen nodes at intervals. Cells angular with disc-shaped chloroplasts. |
| Lyngbya, Lyngbya aestuarii |
1 2 3 4 5 6 7 | filamentous
Cyanobacterium:sheathed, unbranched, no heterocysts, forms hormogonia
(short filaments) which can escape from the thin sheath and may show motility.
cf Oscillatoria: motile but no sheath, and Phormidium: sheaths
form a mat. Trichome (filament not including sheath) colour ranges from
olive green to brown or black; sheath colourless or brown when older. L. aestuarii is a brackish-water species: the examples shown came from water with a salinity value of 9. |