Phylum: Charophyta Family: Desmidiaceae
Xanthidium impar (J.P. Jacobsen) G. Deflandre 1929
First described and illustrated by Jacobsen (1876: 211, pl. 8: 28) as Xanthidium octocorne f. impar. It was later raised to species level by Deflandre (1929: 137). The species has been observed several times with secondary short spines.
Cell dimensions: L: 29-37.5 µm; B: 28-35 µm; Is: 9.6-12.5 µm; Sp: 10-14 µm; overall LxB: 59-69 x 50-72.
A very rare desmid found in acidic moorland pools and bogs.
References:
Deflandre, G. (1929). Notes sure l'Arthrodesmus impar (Jacobsen) Grönbl. et ses veriations, suivies de remarques sur la delimitation des genres Arthrodesmus et Xanthidium.
Jacobsen, J.P. (1875).. Aperçu systématique et critique sur les Desmidiacées du Danemark.
John, D.M. & Williamson, D.B. (2009).. A Practical Guide to the Desmids of the West of Ireland.