Phylum: Heterokontophyta   Family: Pleourochloridiaceae

Pseudogoniochloris tripus (A. Pascher) L. Krienitz, E. Hegewald, O.L. Reymond & T. Peschke 1993

First described and illustrated by Pascher (1938: 623, fig. 482) as Goniochloris tripus. More recently it has been moved to its current position by Krienitz, Hegewald, Reymond & Peschke (1993: 80). A very small triangular alga with some variation in the thickness of the arms.
Cell diameters: 20-40 µm.
Being so small and often in the benthic layer, it is easily overlooked. Found in circum-neutral waters.

References: 
Krienitz, L., Hegewald, E., Reymond, O.L. & Peschke, T. (1993) Variability of LM, TEM and SEM characteristics of Pseudogoniochloris tripus gen. et comb. nov. (Xanthophyceae).
John, D.M., Whitton, B.A. & Brook, A.J. (2011 second edition) The Freshwater Algal Flora of the British Isles.
Pascher, A.(1938) Heterokonten. In: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz.