Vegetative cell of Spirotaenia diplohelica. Notice two spirally twisted chloroplast bands merging into a reddish-cloured cap at the cell ends.

Cell dimensions (L x B): 37 x 7 µm



Desmid of the month
April 2019

Spirotaenia diplohelica

As its name indicates, Spirotaenia diplohelica is marked by a chloroplast in the form of a double helix. Actually, the chloroplast consists of two spirally twisted parietal bands that at the cell poles merge into a reddish-coloured cap. The globose zygospore is furnished with transparent, conical protuberances deviating from all other known desmid zygospores (Coesel et al. 2017). In the Netherlands, Spirotaenia diplohelica is of rather rare occurrence in acidic, oligotrophic moorland pools. Zygospores are only known from nearby Flanders.

Coesel, P.F.M., Vanhoof, A & Meesters, J., 2007. Zygospore morphology in the conjugating green alga Spirotaenia diplohelica. — Phytotaxa 329: 284-288.

Young zygospore of Spirotaenia diplohelica with remnants of gametangial cells still stuck to it.

Older zygospore of Spirotaenia diplohelica. Notice conical, transparent protuberances overlaid by a hyaline membrane.