Image © Marien van Westen
Euastrum luetkemuelleri. Notice rather small cell size, trapeziform semicell outline and slight apical indentations.
Cell dimensions (L x B): 25 x 18 µm
Eu. luetkemuelleri is one of the Euastrum species that may be confused with small-sized Cosmaria. Euastrum-specific features such as an apical median indentation, a dilated apical lobe and a central inflation of the semicell are but weakly developed. A differentiating characteristic with respect to the somewhat similar Eu. insulare (desmid of June 2016) is in the expression of lateral semicell lobes: distinctly developed (usually even stronger than the basal lobes) in Eu. insulare, hardly developed in Eu. luetkemuelleri resulting in a somewhat trapezoid outline of the semicell. In the Netherlands, Eu. luetkemuelleri is very rare, only known from some oligo-mesotrophic moorland pools.
Image © Koos Meesters (after Czech material)
Another cell of Eu. luetkemuelleri with rudimentary lateral lobes.
Image © Koos Meesters (after Irish material)
Empty cell of Eu. luetkemuelleri with somewhat better developed lateral semicell lobes. Semicells show a subapical, curved, transversal furrow in the cell wall referring to the questionable var. carniolicum.
SEM picture of Euastrum luetkemuelleri var. carniolicum.
Image © Jan Šťastný