Euastrum pseudotuddalense. Notice small cell dimensions and semicells with more or less rectangular apical lobes abruptly passing into rounded basal lobes.

Cell dimensions (L x B): 16 x 14 µm.



Desmid of the month
August 2013

Euastrum pseudotuddalense

Eu. pseudotuddalense is a small, little-known Euastrum species that may be readily confused with some other, similarly shaped taxa, a number of which are most likely identical (Coesel & Van Westen 2013). As for its geographical distribution, Eu. pseudotuddalense (as well as its supposed relatives) is concentrated in arctic-alpine regions. In morphology and cell dimensions Eu. pseudotuddalense roughly resembles Eu. binale, in particular its common and widely spread var. gutwinskii. It differs from that taxon by the lack of lateral lobes (only apical and basal lobes are to be distinguished) and a more pronounced central protuberance. Whereas Eu. binale is characterized by semicells that are trapezoid-pyramidal in outline, those in Eu. pseudotuddalense are made up of a more or less rectangular basal part abruptly separated from a likewise, but smaller rectangular apical part. In the Netherlands, Eu. pseudotuddalense is only known from the province of Drenthe (the coldest province of the country!) where it is locally rather common in mesotrophic, slightly acidic pools on sandy soil.

Coesel, P.F.M. & Van Westen, M., 2013. Taxonomic notes on Dutch desmids V (Streptophyta, Desmidiales): new species, new morphological features. — Phytotaxa 84: 46-54.

SEM picture of Eu. pseudotuddalense in frontal view. Notice scrobiculate cell wall and scattered granules at the semicell lobes.

SEM picture of Eu. pseudotuddalense in apical view. Notice prominent central protuberance.