Cells single. Usually somewhat longer than broad, with a deep median constriction. Semicells oval, elliptical or polygonal in front view, with flattened apex. Spines on lateral margins, often in pairs. A single protuberance in the centre of each semicell, with a distinctive pattern of granules or pores. One or two parietal chloroplasts per semicell, with 1-2 pyrenoids each.
Most taxa occur in boggy/peaty pools or in the metaphyton of oligotrophic lakes, others are planktonic.
Number of taxa described from Britain: 15 species, 24 varieties
Xanthidium subhastiferum |
Xanthidium antilopeum |
Xanthidium cristatum |
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