Cosmarium cf. crenatum Ralfs
Reference: Ralfs 1848
Compare with: Cosmarium fo. crenatum fo.; Cosmarium costatum var. gutwinskii
Remarks: The outlines of the cells of the specimens depicted below are quite similar to the outlines of the cells in Ralfs' original images, but because he describes the 'frond' only as punctate, a classification as such is not justifiable. Oddly enough in literature various forms are described as the nominate variety or as a separate variety of Cosmarium crenatum, that have the typical ornamentation, consisting of vertical rows of costae, like the images depicted below. This form and all the other mentioned forms must be newly described. The specimen on this page, all originating from puddles, has five crenations on each side of the semicell and four at the apex. Sometimes a small granule is visible at the basal corner.
C0667
2008011001
C0667
2008011001
C0667
2008011001
2008011-001
Front view
Netherlands
2008011-001
Side view
Netherlands
2008011-001
Side view
Netherlands
C0667
2016008014
C0667
2016008014
C0667
2016008014
2016008-014
Front view
Netherlands
2016008-014
Side view
Netherlands
2016008-014
Side view
Netherlands
C0667
2009002001
C0667
2012004048
C0667
2012004049
2009002-001
Side view
Netherlands
Focus on the reverse side
2012004-048
Front view
Netherlands
2012004-049
Oblique view
Netherlands
Focus on the reverse side
All photos copyright: © 2009-2021 Alfred van Geest - Send comments to asvg@xs4all.nl