Pals et al. 1980: Zygospores square, smooth, measuring (25)28-30(39) micron each way, with sides normally concave. The retuse angles (the former points of attachment of the vegetative cells) 4-7 micron in diameter. Diameter of the depression in each angle about 3 micron.
Pals JP, van Geel B, Delfos A (1980) Palaeoecological studies in the Klokkeweel bog near Hoogkarspel (prov of Noord-Holland). Rev. Palaeobot. Palynol. 30:371-418.