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 |
|---|---|---|
| Actinotaenium curtum | 1 | 'Saccoderm' desmid |
| Amphora veneta | 1 | diatom |
| Anabaena | 1 2 | planktonic filamentous Cyanobacteria: beaded cells with heterocysts & akinetes |
| Anabaena spiroides | 1 | |
| Anabaena flos-aquae | 1 2 3 4 5 6 | |
| Ankistrodesmus | 1 2 | colonial Chlorophyte: clustered needle-like cells |
| Ankistrodesmus falcatus | 1 | |
| Ankistrodesmus fusiformis | 1 2 3 | |
| ?Apatococcus | 1 | colonial Chlorophyte: like Desmococcus, this is usually considered subaerial, found on stones, walls, etc. |
| Aphanizomenon flos-aquae | 1 2 | Filamentous cyanobacterium, clusters in floating bundles, bloom-forming. Filaments usually with heterocysts visible. |
| Aphanocapsa | 1 2 3 4 5 | colonial Cyanobacteria: cells in a common mucilage sheath |
| Aphanocapsa delicatissima | 1 | |
| Aphanocapsa elachista | 1 2 3 4 | |
| Aphanocapsa grevillei | 1 | |
| Aphanochaete | 1 2 3 | filamentous Chlorophyte: epiphytic on other algae; cells have setae |
| Aphanothece | 1 | colonial Cyanobacteria: cells in a common mucilage sheath |
| Aphanothece castagnei | 1 | |
| Aphanothece clathrata | ||
| Aphanothece microscopica | 1 2 | |
| Aphanothece stagnina | 1 2 3 4 5 6 | |
| Apiocystis | 1 2 3 | colonial Chlorophyte: cells in a common mucilage sheath, with setae projecting beyond the sheath |
| Asterionella formosa | 1 2 | colonial Diatom: long cells in stellate formation |
| Asterocystis (Chroodactylon) | 1 2 3 4 5 6 | filamentous Rhodophyte: false-branched filaments with stellate chloroplasts and pyrenoid: frequently blue-green |
| Asterococcus | 1 2 3 4 ?5 ?6 7 8 | |
| Asterococcus limneticus | 1 2 3 4 | colonial Chlorophyte: small numbers of cells in a concentrically layered mucilage; chloroplast stellate |
| Audouinella | 1 2 3 4 5 6 | filamentous Rhodophyte: relatively short filaments sometimes forming a reddish turf on rocks, etc., branched with red (sometimes grey-green) disclike chloroplasts |
| Aulacoseira (Melosira) | 1 2 3 | filamentous centric (pill-box shaped) Diatom; cells linked by spines, chloroplasts discoid |
| Name | Image Links | Description |
|---|---|---|
| Bambusina | 1 2 3 | filamentous desmid |
| Batrachospermum | 1 2 3 4 5 6 7 8 9 10 11 12 13 | filamentous Rhodophyte: branched, with smaller braches in tufts or whorls, giving the plant a beaded appearance ("Frog-spawn alga") |
| Binuclearia | 1 2 3 4 | filamentous Chlorophyte: cells usually grouped in pairs with thickened, lamellate cell walls |
| Botrydium | 1 2 3 | Siphonaceous xanthophyte, consisting of a bulbous aerial thallus with colourless branching rhizoids growing in drying mud at the edge of ponds. |
| Botryococcus | 1 2 3 4 5 6 7 8 9 10 11 12 13 | colonial Chlorophyte: planktonic, sometimes bloom-forming. Colony is very dense making cells hard to see, contains yellow oil droplets which can be squeezed out under a coverslip |
| Bulbochaete | 1 2 3 4 5 | filamentous Chlorophyte; branched with tapering cells each of which bears a hair cell with a bulbous base. |