Platessa saxonica (Krasske ex Hustedt) C.E.Wetzel, Lange-Bertalot & Ector; 2017; 220

Synonymy

Achnanthes saxonica Krasske ex Hustedt 1933; 403

Key references

Wetzel C.E., Lange-Bertalot H., Ector E. 2017. Type analysis of Achnanthes oblongella Østrup and resurrection of Achnanthes saxonica Krasske (Bacillariophyta). Nova Hedwigia Beiheft. 146: 209-227.

Morphology

Size
8.0-15.5 µm long, 4.8-5.7 µm wide (UK population), 6.7-19 µm long , 4.3-6.0 µm wide (European populations, Wetzel et al. 2017).

Shape
Elliptic with broadly rounded apices.

Symmetry
Isopolar, bilaterally symmetrical, heterovalvar.

Striae
Raphe valve: radiate, becoming more strongly radiate near apices, 25-30 in 10 µm; rapheless valve: more or less parallel at valve centre becoming radiate, and strongly radiate near apices, 11-15 in 10 µm (Wetzel et al. 2017), areolae indistinct.

Axial area
Raphe valve: narrow, linear; rapheless valve: linear, expanding slightly towards the valve centre in medium and larger valves.

Central area
Raphe valve: somewhat irregular, rectangular or slightly acute-angled sub-fascia, bordered by 1-3 very short striae; rapheless valve: indistinct, occasionally small irregular and bordered by a slightly shortened central stria.

Raphe
Filiform with expanded proximal ends.

SEM morphology
Raphe valve: striae uniseriate; rapheless valve: striae biseriate, rarely becoming uniseriate towards the axial area; restricted to the valve face and occluded; on the mantle, adjacent to each stria, but separated by a hyaline area, is a row of double areolae.

Literature

References are given in chronological order.

Reference	Citation
Hustedt F. 1933. Die Kieselalgen Deutschlands, Österreichs und der Schweiz unter Berücksichtigung der übrigen Länder Europas sowie der angrenzenden Meeresgebiete. 7 (Teil 2, Lief. 3). In: L. Rabenhorst (ed.), Kryptogamen Flora von Deutschland, Österreich und der Schweiz. Akademische Verlagsgesellschaft m.b.h., Leipzig. 321-433 pp; 781-880 pls.	Morphology; Illustrations; Description; Taxonomy
Lange-Bertalot H., Krammer K. 1989. Achnanthes eine Monographie der Gattung mit Definition der Gattung Cocconeis und Nachträgen zu den Naviculaceae. Bibliotheca Diatomologica Vol. 18. 393 pp; 100 pls	Morphology; Illustrations
Lange-Bertalot H., Külbs K., Lauser T., Nörpel-Schempp M., Willmann M. 1996. Diatom Taxa introduced by Georg Krasske Documentation and Revision. Iconographia Diatomologica Vol. 3, Lange-Bertalot H. (ed.), Koeltz Scientific Books, Königstein. 358 pp	Morphology; Illustrations
Wetzel C.E., Lange-Bertalot H., Ector E. 2017. Type analysis of Achnanthes oblongella Østrup and resurrection of Achnanthes saxonica Krasske (Bacillariophyta). Nova Hedwigia Beiheft. 146: 209-227.	Morphology; Taxonomy; Illustrations; Ecology

Similar species not published on this website:

This page should be cited as:

Wetzel C.E., Lange-Bertalot H., Ector L., Van de Vijver B., Jüttner I. Platessa saxonica (Krasske ex Hustedt) C.E.Wetzel, Lange-Bertalot & Ector; 2017; 220. In: Jüttner I., Carter C., Cox E.J., Ector L., Jones V., Kelly M.G., Kennedy B., Mann D.G., Turner J. A., Van de Vijver B., Wetzel C.E., Williams D.M.. Freshwater Diatom Flora of Britain and Ireland. Amgueddfa Cymru - National Museum Wales. Available online at https://naturalhistory.museumwales.ac.uk/diatoms/browsespecies.php?-recid=4530. [Accessed: ].