Image © Koos Meesters (after Austrian material)
Euastrum ventricosum. Notice cell roughly similar to that of Eu. crassum but smaller and more thick-set.
Cell dimensions (L x B): ca 100 x 60 µm
Euastrum ventricosum much resembles Eu. crassum and, likely, is closely affiliated to it. As compared to that latter species, Eu. ventricosum has somewhat smaller cells with a lower length to breadth ratio. An additional differentiating feature is the presence of two tumours in the median part of the semicell that are hardly or not developed in Eu. crassum. Eu. ventricosum has a predominantly atlantic-arctic distribution. Formerly it was known from the Netherlands but it was not found again since the 1930's.
Cell of Eu. ventricosum showing scrobiculate wall with a larger pit in the semicell centre.
Image © Koos Meesters (after Irish material)
Semicell of Eu. crassum (left) next to a cell of Eu. ventricosum (right) as an illustration of the different cell size of those species.
Image © Jan Šťastný (after Austrian material)
SEM picture of Eu. ventricosum showing cell wall sculpture in detail. Notice some two groups of concentric series of scrobicles in the median part of the semicell marking tumour-like inflations.