of the month
holmiense belongs to a group of desmid species
characterized by a predominantly arctic-alpine distribution. Remarkably
enough, part of those species may also be encountered in European lowland
regions, particularly in hemi-atmophytic, pH circumneutral habitats. Such
environmental conditions are, e. g., met with in shallow dune pools which
dry out periodically. In the Dutch Dune District Cosmarium holmiense,
in particular var. integrum, is far from rare; especially sampling
of wet moss cushions may be lucrative.
holmiense var. integrum may be recognized
readily by its broad isthmus and especially by semicells which are abruptly
constricted just below the apex.
holmiense var. integrum (in between
a cell of the diatom Synedra and part of a filament of the green
alga Zygnema) as encountered in a Dutch dune pool.
dimensions (L x B): ca 55 x 30 µm.